diff --git a/applications/asset_tracker_v2/src/cloud/cloud_codec/lwm2m/lwm2m_codec_helpers.h b/applications/asset_tracker_v2/src/cloud/cloud_codec/lwm2m/lwm2m_codec_helpers.h
index 50ed91bcb4e9..fb7bfe174a23 100644
--- a/applications/asset_tracker_v2/src/cloud/cloud_codec/lwm2m/lwm2m_codec_helpers.h
+++ b/applications/asset_tracker_v2/src/cloud/cloud_codec/lwm2m/lwm2m_codec_helpers.h
@@ -148,7 +148,7 @@ int lwm2m_codec_helpers_set_neighbor_cell_data(struct cloud_data_neighbor_cells
 
 /** @brief Generate path lists with reference to objects.
  *	   This function outputs a list of paths that can be used to reference objects that should
- *	   be updated (sent to server) when calling the lwm2m_send() function.
+ *	   be updated (sent to server) when calling the lwm2m_send_cb() function.
  *
  *  @param[out] output Pointer to structure into which the input path list will be added.
  *  @param[in]  path List that contains LwM2M paths that will be
diff --git a/applications/asset_tracker_v2/src/cloud/lwm2m_integration/configuration_object.c b/applications/asset_tracker_v2/src/cloud/lwm2m_integration/configuration_object.c
index c5478561abd3..ea7a9753cef0 100644
--- a/applications/asset_tracker_v2/src/cloud/lwm2m_integration/configuration_object.c
+++ b/applications/asset_tracker_v2/src/cloud/lwm2m_integration/configuration_object.c
@@ -103,7 +103,7 @@ static struct lwm2m_engine_obj_inst *object_create(uint16_t obj_inst_id)
 	return &inst;
 }
 
-static int object_init(const struct device *dev)
+static int object_init(void)
 {
 	struct lwm2m_engine_obj_inst *obj_inst = NULL;
 	int ret = 0;
diff --git a/applications/asset_tracker_v2/src/cloud/lwm2m_integration/lwm2m_integration.c b/applications/asset_tracker_v2/src/cloud/lwm2m_integration/lwm2m_integration.c
index dac4983068b0..1e81f69bdc57 100644
--- a/applications/asset_tracker_v2/src/cloud/lwm2m_integration/lwm2m_integration.c
+++ b/applications/asset_tracker_v2/src/cloud/lwm2m_integration/lwm2m_integration.c
@@ -464,13 +464,14 @@ int cloud_wrap_data_send(char *buf, size_t len, bool ack, uint32_t id,
 {
 	ARG_UNUSED(buf);
 	ARG_UNUSED(len);
+	ARG_UNUSED(ack);
 	ARG_UNUSED(id);
 
 	int err;
 
-	err = lwm2m_send(&client, path_list, len, ack);
+	err = lwm2m_send_cb(&client, path_list, len, NULL);
 	if (err) {
-		LOG_ERR("lwm2m_send, error: %d", err);
+		LOG_ERR("lwm2m_send_cb, error: %d", err);
 		return err;
 	}
 
@@ -487,13 +488,14 @@ int cloud_wrap_ui_send(char *buf, size_t len, bool ack, uint32_t id,
 {
 	ARG_UNUSED(buf);
 	ARG_UNUSED(len);
+	ARG_UNUSED(ack);
 	ARG_UNUSED(id);
 
 	int err;
 
-	err = lwm2m_send(&client, path_list, len, ack);
+	err = lwm2m_send_cb(&client, path_list, len, NULL);
 	if (err) {
-		LOG_ERR("lwm2m_send, error: %d", err);
+		LOG_ERR("lwm2m_send_cb, error: %d", err);
 		return err;
 	}
 
diff --git a/applications/asset_tracker_v2/src/cloud/nrf_cloud_integration.c b/applications/asset_tracker_v2/src/cloud/nrf_cloud_integration.c
index 3c92147b51c7..064a1ae1cfdf 100644
--- a/applications/asset_tracker_v2/src/cloud/nrf_cloud_integration.c
+++ b/applications/asset_tracker_v2/src/cloud/nrf_cloud_integration.c
@@ -57,12 +57,11 @@ static struct dfu_target_fmfu_fdev ext_flash_dev = {
 	.dev = DEVICE_DT_GET_ONE(jedec_spi_nor)
 };
 
-static int fmfu_and_modem_init(const struct device *dev)
+static int fmfu_and_modem_init(void)
 {
 	enum nrf_cloud_fota_type fota_type = NRF_CLOUD_FOTA_TYPE__INVALID;
 	int ret;
 
-	ARG_UNUSED(dev);
 
 	/* Check if a full modem FOTA job is pending */
 	ret = nrf_cloud_fota_pending_job_type_get(&fota_type);
diff --git a/applications/asset_tracker_v2/src/ext_sensors/ext_sensors.c b/applications/asset_tracker_v2/src/ext_sensors/ext_sensors.c
index 6474f6a48f7e..0aa9b7650de8 100644
--- a/applications/asset_tracker_v2/src/ext_sensors/ext_sensors.c
+++ b/applications/asset_tracker_v2/src/ext_sensors/ext_sensors.c
@@ -81,7 +81,21 @@ static struct env_sensor accel_sensor_lp = {
 	.dev = DEVICE_DT_GET(DT_ALIAS(accelerometer)),
 };
 
+static struct sensor_trigger adxl362_sensor_trigger_motion = {
+		.chan = SENSOR_CHAN_ACCEL_XYZ,
+		.type = SENSOR_TRIG_MOTION
+};
+
+static struct sensor_trigger adxl362_sensor_trigger_stationary = {
+		.chan = SENSOR_CHAN_ACCEL_XYZ,
+		.type = SENSOR_TRIG_STATIONARY
+};
+
 #if defined(CONFIG_EXTERNAL_SENSORS_IMPACT_DETECTION)
+static struct sensor_trigger adxl372_sensor_trigger = {
+	.chan = SENSOR_CHAN_ACCEL_XYZ,
+	.type = SENSOR_TRIG_THRESHOLD
+};
 /** Sensor struct for the high-G accelerometer */
 static struct env_sensor accel_sensor_hg = {
 	.channel = SENSOR_CHAN_ACCEL_XYZ,
@@ -128,7 +142,7 @@ static void accelerometer_trigger_handler(const struct device *dev,
 
 		break;
 	default:
-		LOG_ERR("Unknown trigger");
+		LOG_ERR("Unknown trigger: %d", trig->type);
 	}
 }
 
@@ -221,13 +235,8 @@ int ext_sensors_init(ext_sensor_handler_t handler)
 		evt.type = EXT_SENSOR_EVT_ACCELEROMETER_ERROR;
 		evt_handler(&evt);
 	} else {
-		struct sensor_trigger trig = {
-			.chan = SENSOR_CHAN_ACCEL_XYZ,
-			.type = SENSOR_TRIG_THRESHOLD
-		};
-
 		int err = sensor_trigger_set(accel_sensor_hg.dev,
-					     &trig, impact_trigger_handler);
+					     &adxl372_sensor_trigger, impact_trigger_handler);
 		if (err) {
 			LOG_ERR("Could not set trigger for device %s, error: %d",
 				accel_sensor_hg.dev->name, err);
@@ -436,20 +445,15 @@ int ext_sensors_inactivity_timeout_set(double inact_time)
 int ext_sensors_accelerometer_trigger_callback_set(bool enable)
 {
 	int err;
-	struct sensor_trigger trig = {
-		.chan = SENSOR_CHAN_ACCEL_XYZ,
-		.type = SENSOR_TRIG_MOTION
-	};
 	struct ext_sensor_evt evt = {0};
 
 	sensor_trigger_handler_t handler = enable ? accelerometer_trigger_handler : NULL;
 
-	err = sensor_trigger_set(accel_sensor_lp.dev, &trig, handler);
+	err = sensor_trigger_set(accel_sensor_lp.dev, &adxl362_sensor_trigger_motion, handler);
 	if (err) {
 		goto error;
 	}
-	trig.type = SENSOR_TRIG_STATIONARY;
-	err = sensor_trigger_set(accel_sensor_lp.dev, &trig, handler);
+	err = sensor_trigger_set(accel_sensor_lp.dev, &adxl362_sensor_trigger_stationary, handler);
 	if (err) {
 		goto error;
 	}
diff --git a/applications/asset_tracker_v2/src/main.c b/applications/asset_tracker_v2/src/main.c
index a0151b08f607..3c5638d3d0cc 100644
--- a/applications/asset_tracker_v2/src/main.c
+++ b/applications/asset_tracker_v2/src/main.c
@@ -500,7 +500,7 @@ static void on_all_events(struct app_msg_data *msg)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 	struct app_msg_data msg = { 0 };
@@ -566,6 +566,7 @@ void main(void)
 
 		on_all_events(&msg);
 	}
+	return 0;
 }
 
 APP_EVENT_LISTENER(MODULE, app_event_handler);
diff --git a/applications/asset_tracker_v2/src/modules/ui_module.c b/applications/asset_tracker_v2/src/modules/ui_module.c
index 6f610fee16ab..c5537d0aa434 100644
--- a/applications/asset_tracker_v2/src/modules/ui_module.c
+++ b/applications/asset_tracker_v2/src/modules/ui_module.c
@@ -330,9 +330,8 @@ static void led_pattern_update_work_fn(struct k_work *work)
 	}
 }
 
-static int setup(const struct device *dev)
+static int setup(void)
 {
-	ARG_UNUSED(dev);
 
 	int err;
 
diff --git a/applications/asset_tracker_v2/src/modules/util_module.c b/applications/asset_tracker_v2/src/modules/util_module.c
index 3ff1e48840de..07022003c3d6 100644
--- a/applications/asset_tracker_v2/src/modules/util_module.c
+++ b/applications/asset_tracker_v2/src/modules/util_module.c
@@ -222,9 +222,8 @@ static void reboot_ack_check(uint32_t module_id)
 	}
 }
 
-static int setup(const struct device *dev)
+static int setup(void)
 {
-	ARG_UNUSED(dev);
 
 #if defined(CONFIG_WATCHDOG_APPLICATION)
 	int err = watchdog_init_and_start();
diff --git a/applications/asset_tracker_v2/tests/debug_module/src/debug_module_test.c b/applications/asset_tracker_v2/tests/debug_module/src/debug_module_test.c
index fb2ff72bc599..def78d8c58c3 100644
--- a/applications/asset_tracker_v2/tests/debug_module/src/debug_module_test.c
+++ b/applications/asset_tracker_v2/tests/debug_module/src/debug_module_test.c
@@ -48,8 +48,9 @@ struct event_type __event_type_sensor_module_event;
 struct event_type __event_type_ui_module_event;
 struct event_type __event_type_util_module_event;
 
-/* The following is required because unity is using a different main signature
- * (returns int) and zephyr expects main to not return value.
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
  */
 extern int unity_main(void);
 
@@ -267,7 +268,8 @@ void test_memfault_software_watchdog_trigger_on_callback(void)
 	evt.type = WATCHDOG_EVT_FEED;
 }
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+	return 0;
 }
diff --git a/applications/asset_tracker_v2/tests/location_module/src/location_module_test.c b/applications/asset_tracker_v2/tests/location_module/src/location_module_test.c
index 0327f02fc6fd..89f69cc2a97f 100644
--- a/applications/asset_tracker_v2/tests/location_module/src/location_module_test.c
+++ b/applications/asset_tracker_v2/tests/location_module/src/location_module_test.c
@@ -71,8 +71,9 @@ struct event_type __event_type_modem_module_event;
 
 /* Dummy functions and objects - End.  */
 
-/* The following is required because unity is using a different main signature
- * (returns int) and zephyr expects main to not return value.
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
  */
 extern int unity_main(void);
 
@@ -522,7 +523,8 @@ void test_location_fail_init(void)
 	TEST_ASSERT_EQUAL(0, ret);
 }
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+	return 0;
 }
diff --git a/applications/asset_tracker_v2/tests/lwm2m_codec_helpers/src/lwm2m_codec_helpers_test.c b/applications/asset_tracker_v2/tests/lwm2m_codec_helpers/src/lwm2m_codec_helpers_test.c
index 5327ccb1252a..c15465de581a 100644
--- a/applications/asset_tracker_v2/tests/lwm2m_codec_helpers/src/lwm2m_codec_helpers_test.c
+++ b/applications/asset_tracker_v2/tests/lwm2m_codec_helpers/src/lwm2m_codec_helpers_test.c
@@ -33,6 +33,10 @@
 /* Mon Dec 05 2022 09:38:04 */
 #define UNIX_TIMESTAMP_DUMMY 1670233084418
 
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
+ */
 extern int unity_main(void);
 
 /* Used to verify that the uut properly sets the value that is returned by date_time_now() to
@@ -853,7 +857,8 @@ void test_codec_helpers_object_path_list_generate_too_many_paths(void)
 									    ARRAY_SIZE(path_list)));
 }
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+	return 0;
 }
diff --git a/applications/asset_tracker_v2/tests/lwm2m_integration/src/lwm2m_integration_test.c b/applications/asset_tracker_v2/tests/lwm2m_integration/src/lwm2m_integration_test.c
index ab6ca834a253..a8f7c2c4b469 100644
--- a/applications/asset_tracker_v2/tests/lwm2m_integration/src/lwm2m_integration_test.c
+++ b/applications/asset_tracker_v2/tests/lwm2m_integration/src/lwm2m_integration_test.c
@@ -48,6 +48,10 @@ static int init_security_callback_stub(struct lwm2m_ctx *ctx,
 static int init_firmware_cb_stub(lwm2m_firmware_event_cb_t cb,
 					   int no_of_calls);
 
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
+ */
 extern int unity_main(void);
 
 /* Setup and teardown functions. */
@@ -178,7 +182,7 @@ void test_lwm2m_integration_data_send(void)
 		LWM2M_OBJ(4, 0, 7),
 	};
 
-	__cmock_lwm2m_send_ExpectAndReturn(&client, paths, PATH_LEN, true, 0);
+	__cmock_lwm2m_send_cb_ExpectAndReturn(&client, paths, PATH_LEN, NULL, 0);
 
 	TEST_ASSERT_EQUAL(0, cloud_wrap_data_send(NULL, PATH_LEN, true, 0, paths));
 }
@@ -194,7 +198,7 @@ void test_lwm2m_integration_ui_send(void)
 		LWM2M_OBJ(4, 0, 7),
 	};
 
-	__cmock_lwm2m_send_ExpectAndReturn(&client, paths, PATH_LEN, true, 0);
+	__cmock_lwm2m_send_cb_ExpectAndReturn(&client, paths, PATH_LEN, NULL, 0);
 
 	TEST_ASSERT_EQUAL(0, cloud_wrap_ui_send(NULL, PATH_LEN, true, 0, paths));
 }
@@ -381,7 +385,8 @@ void test_lwm2m_integration_fota_update_image_req(void)
 	TEST_ASSERT_EQUAL(UINT8_MAX, last_cb_type);
 }
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+	return 0;
 }
diff --git a/applications/asset_tracker_v2/tests/nrf_cloud_codec/src/nrf_cloud_codec_test.c b/applications/asset_tracker_v2/tests/nrf_cloud_codec/src/nrf_cloud_codec_test.c
index 87ba4a92c5a7..fa15d83bc03c 100644
--- a/applications/asset_tracker_v2/tests/nrf_cloud_codec/src/nrf_cloud_codec_test.c
+++ b/applications/asset_tracker_v2/tests/nrf_cloud_codec/src/nrf_cloud_codec_test.c
@@ -627,13 +627,14 @@ void test_enc_batch_data_ui_toobig(void)
 }
 
 
-/* It is required to be added to each test. That is because unity is using
- * different main signature (returns int) and zephyr expects main which does
- * not return value.
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
  */
 extern int unity_main(void);
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+	return 0;
 }
diff --git a/applications/asset_tracker_v2/tests/nrf_cloud_codec_mocked_cjson/src/nrf_cloud_codec_mocked_test.c b/applications/asset_tracker_v2/tests/nrf_cloud_codec_mocked_cjson/src/nrf_cloud_codec_mocked_test.c
index 2972085f7770..19aba0aa1fd9 100644
--- a/applications/asset_tracker_v2/tests/nrf_cloud_codec_mocked_cjson/src/nrf_cloud_codec_mocked_test.c
+++ b/applications/asset_tracker_v2/tests/nrf_cloud_codec_mocked_cjson/src/nrf_cloud_codec_mocked_test.c
@@ -553,13 +553,14 @@ void test_enc_config_nomem1(void)
 	TEST_ASSERT_EQUAL(-ENOMEM, ret);
 }
 
-/* It is required to be added to each test. That is because unity is using
- * different main signature (returns int) and zephyr expects main which does
- * not return value.
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
  */
 extern int unity_main(void);
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+	return 0;
 }
diff --git a/applications/asset_tracker_v2/tests/ui_module/src/ui_module_test.c b/applications/asset_tracker_v2/tests/ui_module/src/ui_module_test.c
index c423cf2fda48..7903cd5d9fe9 100644
--- a/applications/asset_tracker_v2/tests/ui_module/src/ui_module_test.c
+++ b/applications/asset_tracker_v2/tests/ui_module/src/ui_module_test.c
@@ -62,8 +62,9 @@ struct event_type __event_type_sensor_module_event;
 struct event_type __event_type_ui_module_event;
 struct event_type __event_type_util_module_event;
 
-/* The following is required because unity is using a different main signature
- * (returns int) and zephyr expects main to not return value.
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
  */
 extern int unity_main(void);
 
@@ -403,7 +404,8 @@ void test_mode_transition(void)
 	verify_publication(true);
 }
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+	return 0;
 }
diff --git a/applications/asset_tracker_v2/tests/ui_module/src/ui_module_test.h b/applications/asset_tracker_v2/tests/ui_module/src/ui_module_test.h
index 4392563605e4..51ade5743edf 100644
--- a/applications/asset_tracker_v2/tests/ui_module/src/ui_module_test.h
+++ b/applications/asset_tracker_v2/tests/ui_module/src/ui_module_test.h
@@ -16,6 +16,6 @@
 /* Suppress linker that warns that setup() is not used. This is because the function is run
  * at SYS_INIT, which is now redefined.
  */
-static int setup(const struct device *dev) __attribute__((unused));
+static int setup(void) __attribute__((unused));
 
 #endif /* UI_MODULE_TEST */
diff --git a/applications/connectivity_bridge/src/main.c b/applications/connectivity_bridge/src/main.c
index ce7101bdc2ed..81d57d67d5bb 100644
--- a/applications/connectivity_bridge/src/main.c
+++ b/applications/connectivity_bridge/src/main.c
@@ -28,11 +28,12 @@ uint8_t *usb_update_sn_string_descriptor(void)
 	return usb_serial_str;
 }
 
-void main(void)
+int main(void)
 {
 	if (app_event_manager_init()) {
 		LOG_ERR("Application Event Manager not initialized");
 	} else {
 		module_set_state(MODULE_STATE_READY);
 	}
+	return 0;
 }
diff --git a/applications/machine_learning/src/main.c b/applications/machine_learning/src/main.c
index b42d58b40c35..fc099ce6aa6b 100644
--- a/applications/machine_learning/src/main.c
+++ b/applications/machine_learning/src/main.c
@@ -13,11 +13,12 @@
 LOG_MODULE_REGISTER(MODULE);
 
 
-void main(void)
+int main(void)
 {
 	if (app_event_manager_init()) {
 		LOG_ERR("Application Event Manager initialization failed");
 	} else {
 		module_set_state(MODULE_STATE_READY);
 	}
+	return 0;
 }
diff --git a/applications/nrf5340_audio/src/bluetooth/Kconfig.defaults b/applications/nrf5340_audio/src/bluetooth/Kconfig.defaults
index f3fcb01b9424..6dfb2b747693 100644
--- a/applications/nrf5340_audio/src/bluetooth/Kconfig.defaults
+++ b/applications/nrf5340_audio/src/bluetooth/Kconfig.defaults
@@ -115,7 +115,6 @@ config BT_MCC
 	default n if WALKIE_TALKIE_DEMO
 	default y
 
-
 config BT_PACS_SNK_CONTEXT
 	default 0x0007 if STREAM_BIDIRECTIONAL
 	default 0x0005
@@ -130,7 +129,12 @@ config BT_CAP_ACCEPTOR
 	default y
 
 config BT_CAP_ACCEPTOR_SET_MEMBER
-	bool
+	default y
+
+config BT_AUDIO_TX
+	default y if STREAM_BIDIRECTIONAL
+
+config BT_AUDIO_RX
 	default y
 
 endif # AUDIO_DEV = 1 (HEADSET)
@@ -194,6 +198,12 @@ config MCTL_LOCAL_PLAYER_CONTROL
 config MCTL_LOCAL_PLAYER_REMOTE_CONTROL
 	default y
 
+config BT_AUDIO_TX
+	default y
+
+config BT_AUDIO_RX
+	default y if STREAM_BIDIRECTIONAL
+
 endif # AUDIO_DEV = 2 (GATEWAY)
 
 endif # TRANSPORT_CIS
@@ -222,6 +232,9 @@ config BT_ISO_SYNC_RECEIVER
 config BT_BAP_BROADCAST_SINK
 	default y
 
+config BT_BAP_SCAN_DELEGATOR
+	default y
+
 config BT_BAP_BROADCAST_SNK_STREAM_COUNT
 	default 2
 
@@ -234,6 +247,9 @@ config BT_SMP
 config BT_PAC_SNK
 	default y
 
+config BT_AUDIO_RX
+	default y
+
 endif # AUDIO_DEV = 1 (HEADSET)
 
 # GATEWAY
@@ -261,6 +277,9 @@ config BT_BAP_BROADCAST_SRC_STREAM_COUNT
 config BT_ISO_MAX_CHAN
 	default 2
 
+config BT_AUDIO_TX
+	default y
+
 endif # AUDIO_DEV = 2 (GATEWAY)
 
 endif # TRANSPORT_BIS
diff --git a/applications/nrf5340_audio/src/bluetooth/ble_audio_services.c b/applications/nrf5340_audio/src/bluetooth/ble_audio_services.c
index 96733d9f971e..4ce8778c9402 100644
--- a/applications/nrf5340_audio/src/bluetooth/ble_audio_services.c
+++ b/applications/nrf5340_audio/src/bluetooth/ble_audio_services.c
@@ -533,8 +533,7 @@ int ble_mcs_discover(struct bt_conn *conn)
 	int ret;
 	uint8_t idx = bt_conn_index(conn);
 
-	if (mcp_mcs_disc_status[idx] == FINISHED ||
-		mcp_mcs_disc_status[idx] == IN_PROGRESS) {
+	if (mcp_mcs_disc_status[idx] == FINISHED || mcp_mcs_disc_status[idx] == IN_PROGRESS) {
 		return -EALREADY;
 	}
 
@@ -570,11 +569,13 @@ int ble_mcs_play_pause(struct bt_conn *conn)
 	int ret = 0;
 	struct mpl_cmd cmd;
 
-	uint8_t idx = bt_conn_index(conn);
+	if (conn != NULL) {
+		uint8_t idx = bt_conn_index(conn);
 
-	if (mcp_mcs_disc_status[idx] != FINISHED) {
-		LOG_WRN("MCS discovery has not finished");
-		return -EBUSY;
+		if (mcp_mcs_disc_status[idx] != FINISHED) {
+			LOG_WRN("MCS discovery has not finished");
+			return -EBUSY;
+		}
 	}
 
 	if (media_player_state == BT_MCS_MEDIA_STATE_PLAYING) {
diff --git a/applications/nrf5340_audio/src/bluetooth/le_audio.h b/applications/nrf5340_audio/src/bluetooth/le_audio.h
index f76b5df5d876..b6b755430173 100644
--- a/applications/nrf5340_audio/src/bluetooth/le_audio.h
+++ b/applications/nrf5340_audio/src/bluetooth/le_audio.h
@@ -50,8 +50,8 @@
 #define BT_AUDIO_CODEC_CAPABILIY_FREQ BT_CODEC_LC3_FREQ_16KHZ
 #endif /* (CONFIG_AUDIO_SAMPLE_RATE_48000_HZ) */
 
-#define BT_AUDIO_LC3_PRESET_CONFIGURABLE(_loc, _stream_context, _bitrate)                          \
-	BT_AUDIO_LC3_PRESET(                                                                       \
+#define BT_BAP_LC3_PRESET_CONFIGURABLE(_loc, _stream_context, _bitrate)                            \
+	BT_BAP_LC3_PRESET(                                                                         \
 		BT_CODEC_LC3_CONFIG(BT_AUDIO_CODEC_CONFIG_FREQ, BT_CODEC_CONFIG_LC3_DURATION_10,   \
 				    _loc, LE_AUDIO_SDU_SIZE_OCTETS(_bitrate), 1, _stream_context), \
 		BT_CODEC_LC3_QOS_10_UNFRAMED(LE_AUDIO_SDU_SIZE_OCTETS(_bitrate),                   \
@@ -62,14 +62,14 @@
 #if CONFIG_TRANSPORT_CIS
 #if CONFIG_BT_BAP_UNICAST_CONFIGURABLE
 #define BT_BAP_LC3_UNICAST_PRESET_NRF5340_AUDIO_SINK                                             \
-	BT_AUDIO_LC3_PRESET_CONFIGURABLE(BT_AUDIO_LOCATION_FRONT_LEFT,                             \
-					 BT_AUDIO_CONTEXT_TYPE_MEDIA,                              \
-					 CONFIG_BT_AUDIO_BITRATE_UNICAST_SINK)
+	BT_BAP_LC3_PRESET_CONFIGURABLE(BT_AUDIO_LOCATION_FRONT_LEFT,                             \
+				       BT_AUDIO_CONTEXT_TYPE_MEDIA,	                         \
+				       CONFIG_BT_AUDIO_BITRATE_UNICAST_SINK)
 
 #define BT_BAP_LC3_UNICAST_PRESET_NRF5340_AUDIO_SOURCE                                           \
-	BT_AUDIO_LC3_PRESET_CONFIGURABLE(BT_AUDIO_LOCATION_FRONT_LEFT,                             \
-					 BT_AUDIO_CONTEXT_TYPE_MEDIA,                              \
-					 CONFIG_BT_AUDIO_BITRATE_UNICAST_SRC)
+	BT_BAP_LC3_PRESET_CONFIGURABLE(BT_AUDIO_LOCATION_FRONT_LEFT,                             \
+				       BT_AUDIO_CONTEXT_TYPE_MEDIA,	                         \
+				       CONFIG_BT_AUDIO_BITRATE_UNICAST_SRC)
 
 #elif CONFIG_BT_BAP_UNICAST_16_2_1
 #define BT_BAP_LC3_UNICAST_PRESET_NRF5340_AUDIO_SINK                                             \
@@ -97,9 +97,9 @@
 #if CONFIG_TRANSPORT_BIS
 #if CONFIG_BT_AUDIO_BROADCAST_CONFIGURABLE
 #define BT_BAP_LC3_BROADCAST_PRESET_NRF5340_AUDIO                                                \
-	BT_AUDIO_LC3_PRESET_CONFIGURABLE(BT_AUDIO_LOCATION_FRONT_LEFT,                             \
-					 BT_AUDIO_CONTEXT_TYPE_MEDIA,                              \
-					 CONFIG_BT_AUDIO_BITRATE_BROADCAST_SRC)
+	BT_BAP_LC3_PRESET_CONFIGURABLE(BT_AUDIO_LOCATION_FRONT_LEFT,                             \
+				       BT_AUDIO_CONTEXT_TYPE_MEDIA,	                         \
+				       CONFIG_BT_AUDIO_BITRATE_BROADCAST_SRC)
 
 #elif CONFIG_BT_BAP_BROADCAST_16_2_1
 #define BT_BAP_LC3_BROADCAST_PRESET_NRF5340_AUDIO                                                \
diff --git a/applications/nrf5340_audio/src/bluetooth/le_audio_bis_gateway.c b/applications/nrf5340_audio/src/bluetooth/le_audio_bis_gateway.c
index f3af8e1551a1..1dd73b5143f0 100644
--- a/applications/nrf5340_audio/src/bluetooth/le_audio_bis_gateway.c
+++ b/applications/nrf5340_audio/src/bluetooth/le_audio_bis_gateway.c
@@ -156,9 +156,13 @@ static void stream_stopped_cb(struct bt_bap_stream *stream, uint8_t reason)
 	}
 }
 
-static struct bt_bap_stream_ops stream_ops = { .sent = stream_sent_cb,
-					       .started = stream_started_cb,
-					       .stopped = stream_stopped_cb };
+static struct bt_bap_stream_ops stream_ops = {
+	.started = stream_started_cb,
+	.stopped = stream_stopped_cb,
+#if (CONFIG_BT_AUDIO_TX)
+	.sent = stream_sent_cb,
+#endif /* (CONFIG_BT_AUDIO_TX) */
+};
 
 #if (CONFIG_AURACAST)
 static void public_broadcast_features_set(uint8_t *features)
diff --git a/applications/nrf5340_audio/src/bluetooth/le_audio_bis_headset.c b/applications/nrf5340_audio/src/bluetooth/le_audio_bis_headset.c
index e4bff1b5c4f9..ab0fc8025488 100644
--- a/applications/nrf5340_audio/src/bluetooth/le_audio_bis_headset.c
+++ b/applications/nrf5340_audio/src/bluetooth/le_audio_bis_headset.c
@@ -78,7 +78,7 @@ static le_audio_receive_cb receive_cb;
 static bool init_routine_completed;
 static bool playing_state = true;
 
-static int bis_headset_cleanup(bool from_sync_lost_cb);
+static int bis_headset_cleanup(void);
 
 static void le_audio_event_publish(enum le_audio_evt_type event)
 {
@@ -185,13 +185,11 @@ static void stream_recv_cb(struct bt_bap_stream *stream, const struct bt_iso_rec
 		bad_frame = true;
 	}
 
-	uint32_t octets_per_sdu = bt_codec_cfg_get_octets_per_frame(stream->codec);
-
-	if (buf->len != octets_per_sdu && bad_frame != true) {
+	if (buf->len != active_stream.codec->octets_per_sdu && bad_frame != true) {
 		data_size_mismatch_cnt++;
 		if ((data_size_mismatch_cnt % 500) == 1) {
 			LOG_DBG("Data size mismatch, received: %d, codec: %d, total: %d", buf->len,
-				octets_per_sdu, data_size_mismatch_cnt);
+				active_stream.codec->octets_per_sdu, data_size_mismatch_cnt);
 		}
 
 		return;
@@ -206,9 +204,13 @@ static void stream_recv_cb(struct bt_bap_stream *stream, const struct bt_iso_rec
 	}
 }
 
-static struct bt_bap_stream_ops stream_ops = { .started = stream_started_cb,
-					       .stopped = stream_stopped_cb,
-					       .recv = stream_recv_cb };
+static struct bt_bap_stream_ops stream_ops = {
+	.started = stream_started_cb,
+	.stopped = stream_stopped_cb,
+#if (CONFIG_BT_AUDIO_RX)
+	.recv = stream_recv_cb,
+#endif /* (CONFIG_BT_AUDIO_RX) */
+};
 
 static bool scan_recv_cb(const struct bt_le_scan_recv_info *info, struct net_buf_simple *ad,
 			 uint32_t broadcast_id)
@@ -264,9 +266,13 @@ static void pa_sync_lost_cb(struct bt_bap_broadcast_sink *sink)
 		return;
 	}
 
+	if (!init_routine_completed) {
+		return;
+	}
+
 	LOG_DBG("Sink disconnected");
 
-	ret = bis_headset_cleanup(true);
+	ret = bis_headset_cleanup();
 	if (ret) {
 		LOG_ERR("Error cleaning up");
 		return;
@@ -352,7 +358,7 @@ static void syncable_cb(struct bt_bap_broadcast_sink *sink, bool encrypted)
 	strncpy(bis_encryption_key, CONFIG_BT_AUDIO_BROADCAST_ENCRYPTION_KEY, 16);
 #endif /* (CONFIG_BT_AUDIO_BROADCAST_ENCRYPTED) */
 
-	if (active_stream.stream->ep->status.state == BT_BAP_EP_STATE_STREAMING || !playing_state) {
+	if (!playing_state) {
 		LOG_DBG("Syncable received, but either in paused_state or already in a stream");
 		return;
 	}
@@ -361,6 +367,8 @@ static void syncable_cb(struct bt_bap_broadcast_sink *sink, bool encrypted)
 
 	ret = bt_bap_broadcast_sink_sync(broadcast_sink, bis_index_bitfields[active_stream_index],
 					 audio_streams_p, bis_encryption_key);
+
+	active_stream.stream = audio_streams_p[active_stream_index];
 	if (ret) {
 		LOG_WRN("Unable to sync to broadcast source, ret: %d", ret);
 		return;
@@ -429,23 +437,19 @@ static int initialize(le_audio_receive_cb recv_cb)
 	return 0;
 }
 
-static int bis_headset_cleanup(bool from_sync_lost_cb)
+static int bis_headset_cleanup(void)
 {
 	int ret;
 
+	init_routine_completed = false;
+
 	ret = bt_bap_broadcast_sink_scan_stop();
 	if (ret && ret != -EALREADY) {
+		LOG_WRN("Failed to stop sink scan, ret: %d", ret);
 		return ret;
 	}
 
 	if (broadcast_sink != NULL) {
-		if (!from_sync_lost_cb) {
-			ret = bt_bap_broadcast_sink_stop(broadcast_sink);
-			if (ret && ret != -EALREADY) {
-				return ret;
-			}
-		}
-
 		ret = bt_bap_broadcast_sink_delete(broadcast_sink);
 		if (ret && ret != -EALREADY) {
 			return ret;
@@ -454,8 +458,6 @@ static int bis_headset_cleanup(bool from_sync_lost_cb)
 		broadcast_sink = NULL;
 	}
 
-	init_routine_completed = false;
-
 	return 0;
 }
 
@@ -492,8 +494,15 @@ static int change_active_brdcast_src(void)
 {
 	int ret;
 
-	/* If the stream has been paused do not stop the sink again */
-	ret = bis_headset_cleanup(!playing_state);
+	if (active_stream.stream->ep->status.state == BT_BAP_EP_STATE_STREAMING) {
+		ret = bt_bap_broadcast_sink_stop(broadcast_sink);
+		if (ret) {
+			LOG_ERR("Failed to stop broadcast sink: %d", ret);
+			return ret;
+		}
+	}
+
+	ret = bis_headset_cleanup();
 	if (ret) {
 		LOG_ERR("Error cleaning up");
 		return ret;
@@ -631,7 +640,7 @@ int le_audio_enable(le_audio_receive_cb recv_cb, le_audio_timestamp_cb timestmp_
 		return ret;
 	}
 
-	ret = bis_headset_cleanup(false);
+	ret = bis_headset_cleanup();
 	if (ret) {
 		LOG_ERR("Error cleaning up");
 		return ret;
@@ -653,7 +662,7 @@ int le_audio_disable(void)
 {
 	int ret;
 
-	ret = bis_headset_cleanup(false);
+	ret = bis_headset_cleanup();
 	if (ret) {
 		LOG_ERR("Error cleaning up");
 		return ret;
diff --git a/applications/nrf5340_audio/src/bluetooth/le_audio_cis_gateway.c b/applications/nrf5340_audio/src/bluetooth/le_audio_cis_gateway.c
index a133a649d7ac..9a424044e499 100644
--- a/applications/nrf5340_audio/src/bluetooth/le_audio_cis_gateway.c
+++ b/applications/nrf5340_audio/src/bluetooth/le_audio_cis_gateway.c
@@ -111,11 +111,11 @@ static bool ble_acl_gateway_all_links_connected(void);
 
 static struct bt_bap_unicast_client_discover_params audio_sink_discover_param[CONFIG_BT_MAX_CONN];
 
-#if CONFIG_STREAM_BIDIRECTIONAL
+#if (CONFIG_BT_AUDIO_RX)
 static struct bt_bap_unicast_client_discover_params audio_source_discover_param[CONFIG_BT_MAX_CONN];
 
 static int discover_source(struct bt_conn *conn);
-#endif /* CONFIG_STREAM_BIDIRECTIONAL */
+#endif /* (CONFIG_BT_AUDIO_RX) */
 
 static void le_audio_event_publish(enum le_audio_evt_type event)
 {
@@ -563,6 +563,7 @@ static void stream_released_cb(struct bt_bap_stream *stream)
 	}
 }
 
+#if (CONFIG_BT_AUDIO_RX)
 static void stream_recv_cb(struct bt_bap_stream *stream, const struct bt_iso_recv_info *info,
 			   struct net_buf *buf)
 {
@@ -600,9 +601,9 @@ static void stream_recv_cb(struct bt_bap_stream *stream, const struct bt_iso_rec
 
 	receive_cb(buf->data, buf->len, bad_frame, info->ts, channel_index);
 }
+#endif /* (CONFIG_BT_AUDIO_RX) */
 
 static struct bt_bap_stream_ops stream_ops = {
-	.sent = stream_sent_cb,
 	.configured = stream_configured_cb,
 	.qos_set = stream_qos_set_cb,
 	.enabled = stream_enabled_cb,
@@ -611,7 +612,12 @@ static struct bt_bap_stream_ops stream_ops = {
 	.disabled = stream_disabled_cb,
 	.stopped = stream_stopped_cb,
 	.released = stream_released_cb,
+#if (CONFIG_BT_AUDIO_RX)
 	.recv = stream_recv_cb,
+#endif /* (CONFIG_BT_AUDIO_RX) */
+#if (CONFIG_BT_AUDIO_TX)
+	.sent = stream_sent_cb,
+#endif /* (CONFIG_BT_AUDIO_TX) */
 };
 
 static void work_stream_start(struct k_work *work)
@@ -855,15 +861,15 @@ static void discover_sink_cb(struct bt_conn *conn, struct bt_codec *codec, struc
 	memset(temp_cap[temp_cap_index].codec, 0, sizeof(temp_cap[temp_cap_index].codec));
 	temp_cap[temp_cap_index].conn = NULL;
 
-#if CONFIG_STREAM_BIDIRECTIONAL
+#if (CONFIG_BT_AUDIO_RX)
 	ret = discover_source(conn);
 	if (ret) {
 		LOG_WRN("Failed to discover source: %d", ret);
 	}
-#endif /* CONFIG_STREAM_BIDIRECTIONAL */
+#endif /* (CONFIG_BT_AUDIO_RX) */
 }
 
-#if CONFIG_STREAM_BIDIRECTIONAL
+#if (CONFIG_BT_AUDIO_RX)
 static void discover_source_cb(struct bt_conn *conn, struct bt_codec *codec, struct bt_bap_ep *ep,
 			       struct bt_bap_unicast_client_discover_params *params)
 {
@@ -972,7 +978,7 @@ static void discover_source_cb(struct bt_conn *conn, struct bt_codec *codec, str
 	memset(temp_cap[temp_cap_index].codec, 0, sizeof(temp_cap[temp_cap_index].codec));
 	temp_cap[temp_cap_index].conn = NULL;
 }
-#endif /* CONFIG_STREAM_BIDIRECTIONAL */
+#endif /* (CONFIG_BT_AUDIO_RX) */
 
 static bool ble_acl_gateway_all_links_connected(void)
 {
@@ -1231,7 +1237,7 @@ static int discover_sink(struct bt_conn *conn)
 	return ret;
 }
 
-#if CONFIG_STREAM_BIDIRECTIONAL
+#if (CONFIG_BT_AUDIO_RX)
 static int discover_source(struct bt_conn *conn)
 {
 	int ret = 0;
@@ -1249,7 +1255,7 @@ static int discover_source(struct bt_conn *conn)
 
 	return ret;
 }
-#endif /* CONFIG_STREAM_BIDIRECTIONAL */
+#endif /* (CONFIG_BT_AUDIO_RX) */
 
 static void security_changed_cb(struct bt_conn *conn, bt_security_t level, enum bt_security_err err)
 {
@@ -1464,11 +1470,11 @@ static int initialize(le_audio_receive_cb recv_cb, le_audio_timestamp_cb timestm
 	for (int i = 0; i < ARRAY_SIZE(pair_params); i++) {
 		pair_params[i].tx_param = &stream_params[stream_iterator];
 		stream_iterator++;
-#if CONFIG_STREAM_BIDIRECTIONAL
+#if (CONFIG_BT_AUDIO_RX)
 		pair_params[i].rx_param = &stream_params[stream_iterator];
 #else
 		pair_params[i].rx_param = NULL;
-#endif /* CONFIG_STREAM_BIDIRECTIONAL */
+#endif /* (CONFIG_BT_AUDIO_RX) */
 		stream_iterator++;
 	}
 
diff --git a/applications/nrf5340_audio/src/bluetooth/le_audio_cis_headset.c b/applications/nrf5340_audio/src/bluetooth/le_audio_cis_headset.c
index 11987271c801..9798b21b9c34 100644
--- a/applications/nrf5340_audio/src/bluetooth/le_audio_cis_headset.c
+++ b/applications/nrf5340_audio/src/bluetooth/le_audio_cis_headset.c
@@ -37,7 +37,7 @@ ZBUS_CHAN_DEFINE(le_audio_chan, struct le_audio_msg, NULL, NULL, ZBUS_OBSERVERS_
 	BT_LE_ADV_PARAM(BT_LE_ADV_OPT_CONNECTABLE, BT_GAP_ADV_FAST_INT_MIN_1,                      \
 			BT_GAP_ADV_FAST_INT_MAX_1, NULL)
 
-#if CONFIG_STREAM_BIDIRECTIONAL
+#if (CONFIG_BT_AUDIO_TX)
 #define HCI_ISO_BUF_ALLOC_PER_CHAN 2
 /* For being able to dynamically define iso_tx_pools */
 #define NET_BUF_POOL_ITERATE(i, _)                                                                 \
@@ -51,7 +51,7 @@ static atomic_t iso_tx_pool_alloc;
 static struct net_buf_pool *iso_tx_pools[] = { LISTIFY(CONFIG_BT_ASCS_ASE_SRC_COUNT,
 							   NET_BUF_POOL_PTR_ITERATE, (,)) };
 /* clang-format on */
-#endif /* CONFIG_STREAM_BIDIRECTIONAL */
+#endif /* (CONFIG_BT_AUDIO_TX) */
 
 #define CSIP_SET_SIZE 2
 enum csip_set_rank { CSIP_HL_RANK = 1, CSIP_HR_RANK = 2 };
@@ -120,9 +120,9 @@ static struct bt_codec lc3_codec = BT_CODEC_LC3(
 
 static enum bt_audio_dir caps_dirs[] = {
 	BT_AUDIO_DIR_SINK,
-#if CONFIG_STREAM_BIDIRECTIONAL
+#if (CONFIG_BT_AUDIO_TX)
 	BT_AUDIO_DIR_SOURCE,
-#endif
+#endif /* (CONFIG_BT_AUDIO_TX) */
 };
 
 static const struct bt_codec_qos_pref qos_pref =
@@ -136,11 +136,11 @@ static struct bt_pacs_cap caps[] = {
 				{
 					 .codec = &lc3_codec,
 				},
-#if CONFIG_STREAM_BIDIRECTIONAL
+#if (CONFIG_BT_AUDIO_TX)
 				{
 					 .codec = &lc3_codec,
 				}
-#endif /* CONFIG_STREAM_BIDIRECTIONAL */
+#endif /* (CONFIG_BT_AUDIO_TX) */
 };
 /* clang-format on */
 
@@ -149,14 +149,14 @@ static struct bt_conn *default_conn;
 static struct bt_bap_stream
 	audio_streams[CONFIG_BT_ASCS_ASE_SNK_COUNT + CONFIG_BT_ASCS_ASE_SRC_COUNT];
 
-#if CONFIG_STREAM_BIDIRECTIONAL
+#if (CONFIG_BT_AUDIO_TX)
 BUILD_ASSERT(CONFIG_BT_ASCS_ASE_SRC_COUNT <= 1,
 	     "CIS headset only supports one source stream for now");
 static struct bt_audio_source {
 	struct bt_bap_stream *stream;
 	uint32_t seq_num;
 } sources[CONFIG_BT_ASCS_ASE_SRC_COUNT];
-#endif /* CONFIG_STREAM_BIDIRECTIONAL */
+#endif /* (CONFIG_BT_AUDIO_TX) */
 
 /* Left or right channel headset */
 static enum audio_channel channel;
@@ -284,7 +284,7 @@ static void advertising_start(void)
 
 static int lc3_config_cb(struct bt_conn *conn, const struct bt_bap_ep *ep, enum bt_audio_dir dir,
 			 const struct bt_codec *codec, struct bt_bap_stream **stream,
-			 struct bt_codec_qos_pref *const pref)
+			 struct bt_codec_qos_pref *const pref, struct bt_bap_ascs_rsp *rsp)
 {
 	LOG_DBG("LC3 configure call-back");
 
@@ -310,7 +310,7 @@ static int lc3_config_cb(struct bt_conn *conn, const struct bt_bap_ep *ep, enum
 				print_codec(codec, dir);
 				le_audio_event_publish(LE_AUDIO_EVT_CONFIG_RECEIVED);
 			}
-#if CONFIG_STREAM_BIDIRECTIONAL
+#if (CONFIG_BT_AUDIO_TX)
 			else if (dir == BT_AUDIO_DIR_SOURCE) {
 				LOG_DBG("BT_AUDIO_DIR_SOURCE");
 				print_codec(codec, dir);
@@ -318,7 +318,7 @@ static int lc3_config_cb(struct bt_conn *conn, const struct bt_bap_ep *ep, enum
 				/* CIS headset only supports one source stream for now */
 				sources[0].stream = audio_stream;
 			}
-#endif /* CONFIG_STREAM_BIDIRECTIONAL */
+#endif /* (CONFIG_BT_AUDIO_TX) */
 			else {
 				LOG_ERR("UNKNOWN DIR");
 				return -EINVAL;
@@ -335,14 +335,16 @@ static int lc3_config_cb(struct bt_conn *conn, const struct bt_bap_ep *ep, enum
 }
 
 static int lc3_reconfig_cb(struct bt_bap_stream *stream, enum bt_audio_dir dir,
-			   const struct bt_codec *codec, struct bt_codec_qos_pref *const pref)
+			   const struct bt_codec *codec, struct bt_codec_qos_pref *const pref,
+			   struct bt_bap_ascs_rsp *rsp)
 {
 	LOG_DBG("ASE Codec Reconfig: stream %p", (void *)stream);
 
 	return 0;
 }
 
-static int lc3_qos_cb(struct bt_bap_stream *stream, const struct bt_codec_qos *qos)
+static int lc3_qos_cb(struct bt_bap_stream *stream, const struct bt_codec_qos *qos,
+		      struct bt_bap_ascs_rsp *rsp)
 {
 	le_audio_event_publish(LE_AUDIO_EVT_PRES_DELAY_SET);
 
@@ -352,7 +354,7 @@ static int lc3_qos_cb(struct bt_bap_stream *stream, const struct bt_codec_qos *q
 }
 
 static int lc3_enable_cb(struct bt_bap_stream *stream, const struct bt_codec_data *meta,
-			 size_t meta_count)
+			 size_t meta_count, struct bt_bap_ascs_rsp *rsp)
 {
 	int ret;
 
@@ -362,7 +364,7 @@ static int lc3_enable_cb(struct bt_bap_stream *stream, const struct bt_codec_dat
 	if (IS_ENABLED(CONFIG_BT_MCC)) {
 		ret = ble_mcs_discover(stream->conn);
 		if (ret == -EALREADY) {
-			LOG_INF("Discovery already run or in progress");
+			LOG_DBG("Discovery already run or in progress");
 		} else if (ret) {
 			LOG_ERR("Failed to start discovery of MCS: %d", ret);
 		}
@@ -371,20 +373,20 @@ static int lc3_enable_cb(struct bt_bap_stream *stream, const struct bt_codec_dat
 	return 0;
 }
 
-static int lc3_start_cb(struct bt_bap_stream *stream)
+static int lc3_start_cb(struct bt_bap_stream *stream, struct bt_bap_ascs_rsp *rsp)
 {
 	LOG_DBG("Start stream %p", (void *)stream);
 	return 0;
 }
 
 static int lc3_metadata_cb(struct bt_bap_stream *stream, const struct bt_codec_data *meta,
-			   size_t meta_count)
+			   size_t meta_count, struct bt_bap_ascs_rsp *rsp)
 {
 	LOG_DBG("Metadata: stream %p meta_count %d", (void *)stream, meta_count);
 	return 0;
 }
 
-static int lc3_disable_cb(struct bt_bap_stream *stream)
+static int lc3_disable_cb(struct bt_bap_stream *stream, struct bt_bap_ascs_rsp *rsp)
 {
 	LOG_DBG("Disable: stream %p", (void *)stream);
 
@@ -393,7 +395,7 @@ static int lc3_disable_cb(struct bt_bap_stream *stream)
 	return 0;
 }
 
-static int lc3_stop_cb(struct bt_bap_stream *stream)
+static int lc3_stop_cb(struct bt_bap_stream *stream, struct bt_bap_ascs_rsp *rsp)
 {
 	LOG_DBG("Stop: stream %p", (void *)stream);
 
@@ -402,7 +404,7 @@ static int lc3_stop_cb(struct bt_bap_stream *stream)
 	return 0;
 }
 
-static int lc3_release_cb(struct bt_bap_stream *stream)
+static int lc3_release_cb(struct bt_bap_stream *stream, struct bt_bap_ascs_rsp *rsp)
 {
 	LOG_DBG("Release: stream %p", (void *)stream);
 
@@ -423,12 +425,12 @@ static const struct bt_bap_unicast_server_cb unicast_server_cb = {
 	.release = lc3_release_cb,
 };
 
+#if (CONFIG_BT_AUDIO_TX)
 static void stream_sent_cb(struct bt_bap_stream *stream)
 {
-#if CONFIG_STREAM_BIDIRECTIONAL
 	atomic_dec(&iso_tx_pool_alloc);
-#endif /* CONFIG_STREAM_BIDIRECTIONAL */
 }
+#endif /* (CONFIG_BT_AUDIO_TX) */
 
 static void stream_recv_cb(struct bt_bap_stream *stream, const struct bt_iso_recv_info *info,
 			   struct net_buf *buf)
@@ -496,9 +498,10 @@ static void stream_stop_cb(struct bt_bap_stream *stream, uint8_t reason)
 {
 	LOG_DBG("Stream %p stopped. Reason: %d", stream, reason);
 
-#if CONFIG_STREAM_BIDIRECTIONAL
+#if (CONFIG_BT_AUDIO_TX)
 	atomic_clear(&iso_tx_pool_alloc);
-#endif /* CONFIG_STREAM_BIDIRECTIONAL */
+#endif /* (CONFIG_BT_AUDIO_TX) */
+
 	le_audio_event_publish(LE_AUDIO_EVT_NOT_STREAMING);
 }
 
@@ -584,12 +587,18 @@ static struct bt_conn_cb conn_callbacks = {
 	.security_changed = security_changed_cb,
 };
 
-static struct bt_bap_stream_ops stream_ops = { .recv = stream_recv_cb,
-					       .sent = stream_sent_cb,
-					       .enabled = stream_enabled_cb,
-					       .started = stream_start_cb,
-					       .stopped = stream_stop_cb,
-					       .released = stream_released_cb };
+static struct bt_bap_stream_ops stream_ops = {
+	.enabled = stream_enabled_cb,
+	.started = stream_start_cb,
+	.stopped = stream_stop_cb,
+	.released = stream_released_cb,
+#if (CONFIG_BT_AUDIO_RX)
+	.recv = stream_recv_cb,
+#endif /* (CONFIG_BT_AUDIO_RX) */
+#if (CONFIG_BT_AUDIO_TX)
+	.sent = stream_sent_cb,
+#endif /* (CONFIG_BT_AUDIO_TX) */
+};
 
 static int initialize(le_audio_receive_cb recv_cb, le_audio_timestamp_cb timestmp_cb)
 {
@@ -857,7 +866,7 @@ int le_audio_play_pause(void)
 
 int le_audio_send(struct encoded_audio enc_audio)
 {
-#if CONFIG_STREAM_BIDIRECTIONAL
+#if (CONFIG_BT_AUDIO_TX)
 	int ret;
 	struct net_buf *buf;
 	static bool hci_wrn_printed;
@@ -910,7 +919,7 @@ int le_audio_send(struct encoded_audio enc_audio)
 		net_buf_unref(buf);
 		atomic_dec(&iso_tx_pool_alloc);
 	}
-#endif /* CONFIG_STREAM_BIDIRECTIONAL */
+#endif /* (CONFIG_BT_AUDIO_TX) */
 
 	return 0;
 }
diff --git a/applications/nrf5340_audio/src/main.c b/applications/nrf5340_audio/src/main.c
index 928919621bb0..864ac4750f48 100644
--- a/applications/nrf5340_audio/src/main.c
+++ b/applications/nrf5340_audio/src/main.c
@@ -164,7 +164,7 @@ void on_ble_core_ready(void)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int ret;
 
diff --git a/applications/nrf5340_audio/src/modules/audio_sync_timer.c b/applications/nrf5340_audio/src/modules/audio_sync_timer.c
index cb30f25dd84e..8784f7759eaf 100644
--- a/applications/nrf5340_audio/src/modules/audio_sync_timer.c
+++ b/applications/nrf5340_audio/src/modules/audio_sync_timer.c
@@ -51,11 +51,10 @@ static void event_handler(nrf_timer_event_t event_type, void *ctx)
  *
  * @return 0 if successful, error otherwise
  */
-static int audio_sync_timer_init(const struct device *unused)
+static int audio_sync_timer_init(void)
 {
 	nrfx_err_t ret;
 
-	ARG_UNUSED(unused);
 
 	ret = nrfx_timer_init(&audio_sync_timer_instance, &cfg, event_handler);
 	if (ret - NRFX_ERROR_BASE_NUM) {
diff --git a/applications/nrf5340_audio/src/modules/power_meas.c b/applications/nrf5340_audio/src/modules/power_meas.c
index ddff6400e329..e7ab2a8d97d7 100644
--- a/applications/nrf5340_audio/src/modules/power_meas.c
+++ b/applications/nrf5340_audio/src/modules/power_meas.c
@@ -102,9 +102,8 @@ static void meas_thread_fn(void *dummy1, void *dummy2, void *dummy3)
 	}
 }
 
-static int power_meas_init(const struct device *dev)
+static int power_meas_init(void)
 {
-	ARG_UNUSED(dev);
 
 	/* check if all sensors are ready */
 	for (size_t i = 0U; i < POWER_RAIL_NUM; i++) {
diff --git a/applications/nrf_desktop/Kconfig.debug b/applications/nrf_desktop/Kconfig.debug
index 934aa9f92ae2..9a960edaca8a 100644
--- a/applications/nrf_desktop/Kconfig.debug
+++ b/applications/nrf_desktop/Kconfig.debug
@@ -30,12 +30,6 @@ choice LOG_MODE
 
 endchoice
 
-config LOG_DEFAULT_LEVEL
-	default 2
-	help
-	  nRF Desktop Logging configuration sets the Warning level as a default
-	  logging level for modules that do not specify their own logging level.
-
 config LOG_MODE_OVERFLOW
 	default y
 	help
diff --git a/applications/nrf_desktop/configuration/nrf52820dongle_nrf52820/child_image/mcuboot/prj_release.conf b/applications/nrf_desktop/configuration/nrf52820dongle_nrf52820/child_image/mcuboot/prj_release.conf
index 943c80666a78..e861ab8425ad 100644
--- a/applications/nrf_desktop/configuration/nrf52820dongle_nrf52820/child_image/mcuboot/prj_release.conf
+++ b/applications/nrf_desktop/configuration/nrf52820dongle_nrf52820/child_image/mcuboot/prj_release.conf
@@ -61,3 +61,4 @@ CONFIG_TIMESLICING=n
 CONFIG_PRINTK=n
 CONFIG_BOOT_BANNER=n
 CONFIG_ERRNO=n
+CONFIG_ARM_MPU=n
diff --git a/applications/nrf_desktop/configuration/nrf52833dk_nrf52820/child_image/mcuboot/prj_release.conf b/applications/nrf_desktop/configuration/nrf52833dk_nrf52820/child_image/mcuboot/prj_release.conf
index f7d106237f90..7516a15d9ad7 100644
--- a/applications/nrf_desktop/configuration/nrf52833dk_nrf52820/child_image/mcuboot/prj_release.conf
+++ b/applications/nrf_desktop/configuration/nrf52833dk_nrf52820/child_image/mcuboot/prj_release.conf
@@ -65,3 +65,4 @@ CONFIG_CONSOLE=n
 CONFIG_UART_CONSOLE=n
 CONFIG_BOOT_BANNER=n
 CONFIG_ERRNO=n
+CONFIG_ARM_MPU=n
diff --git a/applications/nrf_desktop/configuration/nrf52833dk_nrf52833/child_image/mcuboot/prj.conf b/applications/nrf_desktop/configuration/nrf52833dk_nrf52833/child_image/mcuboot/prj.conf
index eea906cbec1e..f0dd2b0f693d 100644
--- a/applications/nrf_desktop/configuration/nrf52833dk_nrf52833/child_image/mcuboot/prj.conf
+++ b/applications/nrf_desktop/configuration/nrf52833dk_nrf52833/child_image/mcuboot/prj.conf
@@ -58,7 +58,6 @@ CONFIG_USE_SEGGER_RTT=y
 CONFIG_LOG_BACKEND_UART=n
 CONFIG_UART_CONSOLE=n
 CONFIG_LOG=y
-CONFIG_LOG_DEFAULT_LEVEL=2
 CONFIG_LOG_MAX_LEVEL=3
 CONFIG_LOG_PRINTK=y
 CONFIG_LOG_MODE_IMMEDIATE=y
diff --git a/applications/nrf_desktop/configuration/nrf52833dongle_nrf52833/child_image/mcuboot/prj.conf b/applications/nrf_desktop/configuration/nrf52833dongle_nrf52833/child_image/mcuboot/prj.conf
index eea906cbec1e..f0dd2b0f693d 100644
--- a/applications/nrf_desktop/configuration/nrf52833dongle_nrf52833/child_image/mcuboot/prj.conf
+++ b/applications/nrf_desktop/configuration/nrf52833dongle_nrf52833/child_image/mcuboot/prj.conf
@@ -58,7 +58,6 @@ CONFIG_USE_SEGGER_RTT=y
 CONFIG_LOG_BACKEND_UART=n
 CONFIG_UART_CONSOLE=n
 CONFIG_LOG=y
-CONFIG_LOG_DEFAULT_LEVEL=2
 CONFIG_LOG_MAX_LEVEL=3
 CONFIG_LOG_PRINTK=y
 CONFIG_LOG_MODE_IMMEDIATE=y
diff --git a/applications/nrf_desktop/configuration/nrf52840dk_nrf52840/child_image/mcuboot/prj_mcuboot_qspi.conf b/applications/nrf_desktop/configuration/nrf52840dk_nrf52840/child_image/mcuboot/prj_mcuboot_qspi.conf
index 95b6336e6b65..7b7d279c1264 100644
--- a/applications/nrf_desktop/configuration/nrf52840dk_nrf52840/child_image/mcuboot/prj_mcuboot_qspi.conf
+++ b/applications/nrf_desktop/configuration/nrf52840dk_nrf52840/child_image/mcuboot/prj_mcuboot_qspi.conf
@@ -34,7 +34,6 @@ CONFIG_BOOT_MAX_IMG_SECTORS=2048
 # Logger
 CONFIG_USE_SEGGER_RTT=y
 CONFIG_LOG=y
-CONFIG_LOG_DEFAULT_LEVEL=2
 CONFIG_LOG_MAX_LEVEL=2
 CONFIG_LOG_PRINTK=y
 CONFIG_LOG_MODE_IMMEDIATE=y
diff --git a/applications/nrf_desktop/configuration/nrf52840dk_nrf52840/child_image/mcuboot/prj_mcuboot_smp.conf b/applications/nrf_desktop/configuration/nrf52840dk_nrf52840/child_image/mcuboot/prj_mcuboot_smp.conf
index f4586f94e00e..12b95e9b70d1 100644
--- a/applications/nrf_desktop/configuration/nrf52840dk_nrf52840/child_image/mcuboot/prj_mcuboot_smp.conf
+++ b/applications/nrf_desktop/configuration/nrf52840dk_nrf52840/child_image/mcuboot/prj_mcuboot_smp.conf
@@ -30,7 +30,6 @@ CONFIG_SOC_FLASH_NRF_EMULATE_ONE_BYTE_WRITE_ACCESS=y
 # Logger
 CONFIG_USE_SEGGER_RTT=y
 CONFIG_LOG=y
-CONFIG_LOG_DEFAULT_LEVEL=2
 CONFIG_LOG_MAX_LEVEL=3
 CONFIG_LOG_PRINTK=y
 CONFIG_LOG_MODE_IMMEDIATE=y
diff --git a/applications/nrf_desktop/src/main.c b/applications/nrf_desktop/src/main.c
index 4de63c2adfc8..f97cca59e91c 100644
--- a/applications/nrf_desktop/src/main.c
+++ b/applications/nrf_desktop/src/main.c
@@ -13,11 +13,12 @@
 LOG_MODULE_REGISTER(MODULE);
 
 
-void main(void)
+int main(void)
 {
 	if (app_event_manager_init()) {
 		LOG_ERR("Application Event Manager not initialized");
 	} else {
 		module_set_state(MODULE_STATE_READY);
 	}
+	return 0;
 }
diff --git a/applications/nrf_desktop/src/modules/hids.c b/applications/nrf_desktop/src/modules/hids.c
index 6e36364b0554..4359cb4085a0 100644
--- a/applications/nrf_desktop/src/modules/hids.c
+++ b/applications/nrf_desktop/src/modules/hids.c
@@ -286,7 +286,7 @@ static int module_init(void)
 	if (IS_ENABLED(CONFIG_DESKTOP_HID_REPORT_MOUSE_SUPPORT)) {
 		static const uint8_t mask[] = REPORT_MASK_MOUSE;
 		BUILD_ASSERT((sizeof(mask) == 0) ||
-			     (sizeof(mask) == ceiling_fraction(REPORT_SIZE_MOUSE, 8)));
+			     (sizeof(mask) == DIV_ROUND_UP(REPORT_SIZE_MOUSE, 8)));
 		BUILD_ASSERT(REPORT_ID_MOUSE < ARRAY_SIZE(report_index));
 
 		input_report[ir_pos].id       = REPORT_ID_MOUSE;
@@ -301,7 +301,7 @@ static int module_init(void)
 	if (IS_ENABLED(CONFIG_DESKTOP_HID_REPORT_KEYBOARD_SUPPORT)) {
 		static const uint8_t mask[] = REPORT_MASK_KEYBOARD_KEYS;
 		BUILD_ASSERT((sizeof(mask) == 0) ||
-			     (sizeof(mask) == ceiling_fraction(REPORT_SIZE_KEYBOARD_KEYS, 8)));
+			     (sizeof(mask) == DIV_ROUND_UP(REPORT_SIZE_KEYBOARD_KEYS, 8)));
 		BUILD_ASSERT(REPORT_ID_KEYBOARD_KEYS < ARRAY_SIZE(report_index));
 
 		input_report[ir_pos].id       = REPORT_ID_KEYBOARD_KEYS;
@@ -316,7 +316,7 @@ static int module_init(void)
 	if (IS_ENABLED(CONFIG_DESKTOP_HID_REPORT_SYSTEM_CTRL_SUPPORT)) {
 		static const uint8_t mask[] = REPORT_MASK_SYSTEM_CTRL;
 		BUILD_ASSERT((sizeof(mask) == 0) ||
-			     (sizeof(mask) == ceiling_fraction(REPORT_SIZE_SYSTEM_CTRL, 8)));
+			     (sizeof(mask) == DIV_ROUND_UP(REPORT_SIZE_SYSTEM_CTRL, 8)));
 		BUILD_ASSERT(REPORT_ID_SYSTEM_CTRL < ARRAY_SIZE(report_index));
 
 		input_report[ir_pos].id       = REPORT_ID_SYSTEM_CTRL;
@@ -331,7 +331,7 @@ static int module_init(void)
 	if (IS_ENABLED(CONFIG_DESKTOP_HID_REPORT_CONSUMER_CTRL_SUPPORT)) {
 		static const uint8_t mask[] = REPORT_MASK_CONSUMER_CTRL;
 		BUILD_ASSERT((sizeof(mask) == 0) ||
-			     (sizeof(mask) == ceiling_fraction(REPORT_SIZE_CONSUMER_CTRL, 8)));
+			     (sizeof(mask) == DIV_ROUND_UP(REPORT_SIZE_CONSUMER_CTRL, 8)));
 		BUILD_ASSERT(REPORT_ID_CONSUMER_CTRL < ARRAY_SIZE(report_index));
 
 		input_report[ir_pos].id       = REPORT_ID_CONSUMER_CTRL;
diff --git a/applications/zigbee_weather_station/configuration/thingy53_nrf5340_cpuapp/app.overlay b/applications/zigbee_weather_station/configuration/thingy53_nrf5340_cpuapp/app.overlay
index 047a3c6cd30a..6c05cef6236a 100644
--- a/applications/zigbee_weather_station/configuration/thingy53_nrf5340_cpuapp/app.overlay
+++ b/applications/zigbee_weather_station/configuration/thingy53_nrf5340_cpuapp/app.overlay
@@ -4,6 +4,12 @@
  * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
  */
 
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
 &i2c1 {
 	status = "okay";
 
@@ -14,6 +20,10 @@
 	};
 };
 
+&timer2 {
+	status = "okay";
+};
+
 /* Disable unused peripherals to reduce power consumption */
 &pwm0 {
 	status = "disabled";
diff --git a/applications/zigbee_weather_station/src/main.c b/applications/zigbee_weather_station/src/main.c
index 6f67c1df686e..3001e53757aa 100644
--- a/applications/zigbee_weather_station/src/main.c
+++ b/applications/zigbee_weather_station/src/main.c
@@ -359,7 +359,7 @@ void zboss_signal_handler(zb_bufid_t bufid)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	#ifdef CONFIG_USB_DEVICE_STACK
 	wait_for_console();
@@ -389,4 +389,6 @@ void main(void)
 
 	/* Start Zigbee stack */
 	zigbee_enable();
+
+	return 0;
 }
diff --git a/boards/arm/nrf52820dongle_nrf52820/board.c b/boards/arm/nrf52820dongle_nrf52820/board.c
index 550631189bbc..9c5f1be696e9 100644
--- a/boards/arm/nrf52820dongle_nrf52820/board.c
+++ b/boards/arm/nrf52820dongle_nrf52820/board.c
@@ -8,9 +8,8 @@
 #include <hal/nrf_power.h>
 #include <hal/nrf_nvmc.h>
 
-static int board_nrf52820dongle_init(const struct device *dev)
+static int board_nrf52820dongle_init(void)
 {
-	ARG_UNUSED(dev);
 
 	/* If the nrf52820dongle board is powered from USB
 	 * (high voltage mode), GPIO output voltage is set to 1.8 volts by
diff --git a/boards/arm/nrf52833dongle_nrf52833/board.c b/boards/arm/nrf52833dongle_nrf52833/board.c
index 1d7f287b8f2a..3d5ed0b13fca 100644
--- a/boards/arm/nrf52833dongle_nrf52833/board.c
+++ b/boards/arm/nrf52833dongle_nrf52833/board.c
@@ -8,9 +8,8 @@
 #include <hal/nrf_power.h>
 #include <hal/nrf_nvmc.h>
 
-static int board_nrf52833dongle_nrf52833_init(const struct device *dev)
+static int board_nrf52833dongle_nrf52833_init(void)
 {
-	ARG_UNUSED(dev);
 
 	/* If the nrf52833dongle_nrf52833 board is powered from USB
 	 * (high voltage mode), GPIO output voltage is set to 1.8 volts by
diff --git a/boards/arm/nrf7002dk_nrf5340/nrf5340_cpuapp_common.dts b/boards/arm/nrf7002dk_nrf5340/nrf5340_cpuapp_common.dts
index c9d916c34062..12865f16c8a6 100644
--- a/boards/arm/nrf7002dk_nrf5340/nrf5340_cpuapp_common.dts
+++ b/boards/arm/nrf7002dk_nrf5340/nrf5340_cpuapp_common.dts
@@ -203,18 +203,6 @@ arduino_i2c: &i2c1 {
 	};
 };
 
-&timer0 {
-	status = "okay";
-};
-
-&timer1 {
-	status = "okay";
-};
-
-&timer2 {
-	status = "okay";
-};
-
 arduino_serial: &uart1 {
 	compatible = "nordic,nrf-uarte";
 	current-speed = <115200>;
diff --git a/boards/arm/nrf7002dk_nrf5340/nrf5340_cpunet_reset.c b/boards/arm/nrf7002dk_nrf5340/nrf5340_cpunet_reset.c
index 3f25f6f788bb..c655d4a3be6f 100644
--- a/boards/arm/nrf7002dk_nrf5340/nrf5340_cpunet_reset.c
+++ b/boards/arm/nrf7002dk_nrf5340/nrf5340_cpunet_reset.c
@@ -32,9 +32,8 @@ static void remoteproc_mgr_config(void)
 #endif /* !defined(CONFIG_TRUSTED_EXECUTION_NONSECURE) */
 }
 
-static int remoteproc_mgr_boot(const struct device *dev)
+static int remoteproc_mgr_boot(void)
 {
-	ARG_UNUSED(dev);
 
 	/* Secure domain may configure permissions for the Network MCU. */
 	remoteproc_mgr_config();
diff --git a/boards/arm/nrf7002dk_nrf5340/nrf7002dk_nrf5340_cpunet.dts b/boards/arm/nrf7002dk_nrf5340/nrf7002dk_nrf5340_cpunet.dts
index 91f0e41eeb72..5c8947b0c920 100644
--- a/boards/arm/nrf7002dk_nrf5340/nrf7002dk_nrf5340_cpunet.dts
+++ b/boards/arm/nrf7002dk_nrf5340/nrf7002dk_nrf5340_cpunet.dts
@@ -138,18 +138,6 @@ arduino_spi: &spi0 {
 	pinctrl-names = "default", "sleep";
 };
 
-&timer0 {
-	status = "okay";
-};
-
-&timer1 {
-	status = "okay";
-};
-
-&timer2 {
-	status = "okay";
-};
-
 &flash1 {
 
 	partitions {
diff --git a/boards/arm/thingy91_nrf9160/adp5360_init.c b/boards/arm/thingy91_nrf9160/adp5360_init.c
index 2b260a534ed8..4f217d9a6d9a 100644
--- a/boards/arm/thingy91_nrf9160/adp5360_init.c
+++ b/boards/arm/thingy91_nrf9160/adp5360_init.c
@@ -94,7 +94,7 @@ static int power_mgmt_init(void)
 	return 0;
 }
 
-static int thingy91_board_init(const struct device *dev)
+static int thingy91_board_init(void)
 {
 	int err;
 
diff --git a/boards/arm/thingy91_nrf9160/thingy91_nrf9160_common.dts b/boards/arm/thingy91_nrf9160/thingy91_nrf9160_common.dts
index ecff87aed4e7..e84476ae8be9 100644
--- a/boards/arm/thingy91_nrf9160/thingy91_nrf9160_common.dts
+++ b/boards/arm/thingy91_nrf9160/thingy91_nrf9160_common.dts
@@ -168,18 +168,6 @@
 	};
 };
 
-&timer0 {
-	status = "okay";
-};
-
-&timer1 {
-	status = "okay";
-};
-
-&timer2 {
-	status = "okay";
-};
-
 &uart0 {
 	compatible = "nordic,nrf-uarte";
 	current-speed = <115200>;
diff --git a/doc/nrf/libraries/modem/lte_lc.rst b/doc/nrf/libraries/modem/lte_lc.rst
index ed372d964884..e8be188e68d7 100644
--- a/doc/nrf/libraries/modem/lte_lc.rst
+++ b/doc/nrf/libraries/modem/lte_lc.rst
@@ -64,7 +64,7 @@ The following block of code shows how the link controller API can be used to est
    	}
    }
 
-   void main(void)
+   int main(void)
    {
    	int err;
 
@@ -73,7 +73,7 @@ The following block of code shows how the link controller API can be used to est
    	err = lte_lc_init_and_connect_async(lte_handler);
    	if (err) {
    		printk("lte_lc_init_and_connect_async, error: %d\n", err);
-   		return;
+   		return 0;
    	}
 
    	k_sem_take(&lte_connected, K_FOREVER);
@@ -108,32 +108,32 @@ For an example implementation, see the following code:
 
    /* ... */
 
-   void main(void)
+   int main(void)
    {
 	int err;
 
 	err = lte_lc_init();
 	if (err) {
 		printk("lte_lc_init, error: %d\n", err);
-		return;
+		return 0;
 	}
 
 	err = lte_lc_psm_req(true);
 	if (err) {
 		printk("lte_lc_psm_req, error: %d\n", err);
-		return;
+		return 0;
 	}
 
 	err = lte_lc_edrx_req(true);
 	if (err) {
 		printk("lte_lc_edrx_req, error: %d\n", err);
-		return;
+		return 0;
 	}
 
 	err = lte_lc_connect_async(lte_handler);
 	if (err) {
 		printk("Connecting to LTE network failed, error: %d\n", err);
-		return;
+		return 0;
 	}
 
 	/* ... */
@@ -173,7 +173,7 @@ The following code block shows a basic implementation of :c:func:`lte_lc_conn_ev
 
    ...
 
-   void main(void)
+   int main(void)
    {
    	int err;
 
@@ -182,7 +182,7 @@ The following code block shows a basic implementation of :c:func:`lte_lc_conn_ev
    	err = lte_lc_init_and_connect_async(lte_handler);
    	if (err) {
    		printk("lte_lc_init_and_connect_async, error: %d\n", err);
-   		return;
+   		return 0;
    	}
 
    	k_sem_take(&lte_connected, K_FOREVER);
@@ -192,7 +192,7 @@ The following code block shows a basic implementation of :c:func:`lte_lc_conn_ev
 	err = lte_lc_conn_eval_params_get(&params);
 	if (err) {
 		printk("lte_lc_conn_eval_params_get, error: %d\n", err);
-		return;
+		return 0;
 	}
 
 	/* Handle connection evaluation parameters... */
@@ -247,10 +247,11 @@ The following code snippet shows how to use :c:macro:`LTE_LC_ON_CFUN` macro:
       printk("Functional mode changed to %d\n", mode);
   }
 
-  void main(void)
+  int main(void)
   {
       /* change functional mode using the Link Controller API */
       lte_lc_func_mode_set(LTE_LC_FUNC_MODE_NORMAL);
+      return 0;
   }
 
 API documentation
diff --git a/doc/nrf/libraries/others/dm.rst b/doc/nrf/libraries/others/dm.rst
index 4588dcfb759f..37619cba8fde 100644
--- a/doc/nrf/libraries/others/dm.rst
+++ b/doc/nrf/libraries/others/dm.rst
@@ -36,11 +36,22 @@ Configuration
 
 To use the Distance Measurement module, complete the following steps:
 
-1. Enable the :kconfig:option:`CONFIG_NRF_DM` Kconfig option.
+1. Enable the :kconfig:option:`CONFIG_DM_MODULE` Kconfig option.
+#. Set the ``ncs,dm-timer`` :ref:`chosen node <zephyr:dt-alias-chosen>` to the TIMER peripheral you wish this module to use.
 #. Include :file:`dm.h` in your :file:`main.c` file.
 #. Call :c:func:`dm_init()` to initialize the module.
 #. Call :c:func:`dm_request_add()` to perform the measurement.
 
+For example, to use the ``TIMER2`` peripheral, set ``ncs,dm-timer`` as follows in a devicetree overlay:
+
+.. code-block:: DTS
+
+   / {
+           chosen {
+                   ncs,dm-timer = &timer2;
+           };
+   };
+
 After synchronizing, the nodes that perform the measurement with each other will issue the measurement request.
 The callback function :c:func:`data_ready` is called when the measurement data is available.
 
diff --git a/drivers/hw_cc310/hw_cc310.c b/drivers/hw_cc310/hw_cc310.c
index 320f971ffbb6..5c5ca0f441af 100644
--- a/drivers/hw_cc310/hw_cc310.c
+++ b/drivers/hw_cc310/hw_cc310.c
@@ -17,9 +17,8 @@
 
 #if CONFIG_HW_CC3XX
 
-static int hw_cc3xx_init_internal(const struct device *dev)
+static int hw_cc3xx_init_internal(void)
 {
-	ARG_UNUSED(dev);
 
 	int res;
 
@@ -33,7 +32,7 @@ static int hw_cc3xx_init_internal(const struct device *dev)
 	return res;
 }
 
-static int hw_cc3xx_init(const struct device *dev)
+static int hw_cc3xx_init(void)
 {
 	int res;
 
@@ -44,7 +43,7 @@ static int hw_cc3xx_init(const struct device *dev)
 	nrf_cc3xx_platform_mutex_init();
 
 	/* Enable the hardware */
-	res = hw_cc3xx_init_internal(dev);
+	res = hw_cc3xx_init_internal();
 	return res;
 }
 
diff --git a/drivers/wifi/nrf700x/zephyr/src/zephyr_wifi_mgmt.c b/drivers/wifi/nrf700x/zephyr/src/zephyr_wifi_mgmt.c
index 38c8570e00ce..645eb37db9c0 100644
--- a/drivers/wifi/nrf700x/zephyr/src/zephyr_wifi_mgmt.c
+++ b/drivers/wifi/nrf700x/zephyr/src/zephyr_wifi_mgmt.c
@@ -348,13 +348,13 @@ int wifi_nrf_get_power_save_config(const struct device *dev,
 }
 
 /* TWT interval conversion helpers: User <-> Protocol */
-static struct twt_interval_float wifi_nrf_twt_ms_to_float(uint32_t twt_interval_ms)
+static struct twt_interval_float wifi_nrf_twt_ms_to_float(uint32_t twt_interval)
 {
 	double mantissa = 0;
 	int exponent = 0;
 	struct twt_interval_float twt_interval_float;
 
-	mantissa = frexp(twt_interval_ms, &exponent);
+	mantissa = frexp(twt_interval, &exponent);
 	/* Ceiling and conversion to milli seconds */
 	twt_interval_float.mantissa = ceil(mantissa * 1000);
 	twt_interval_float.exponent = exponent;
@@ -516,8 +516,8 @@ void wifi_nrf_event_proc_get_power_save_info(void *vif_ctx,
 		twt_zep->dialog_token = twt_rpu->dialog_token;
 		twt_interval_float.mantissa = twt_rpu->twt_target_wake_interval_mantissa;
 		twt_interval_float.exponent = twt_rpu->twt_target_wake_interval_exponent;
-		twt_zep->twt_interval_ms = wifi_nrf_twt_float_to_ms(twt_interval_float);
-		twt_zep->twt_wake_interval_ms = twt_rpu->nominal_min_twt_wake_duration;
+		twt_zep->twt_interval = wifi_nrf_twt_float_to_ms(twt_interval_float);
+		twt_zep->twt_wake_interval = twt_rpu->nominal_min_twt_wake_duration;
 	}
 
 	vif_ctx_zep->ps_config_info_evnt = true;
@@ -554,7 +554,7 @@ int wifi_nrf_set_twt(const struct device *dev,
 	switch (twt_params->operation) {
 	case WIFI_TWT_SETUP:
 		struct twt_interval_float twt_interval_float =
-			wifi_nrf_twt_ms_to_float(twt_params->setup.twt_interval_ms);
+			wifi_nrf_twt_ms_to_float(twt_params->setup.twt_interval);
 
 		twt_info.twt_flow_id = twt_params->flow_id;
 		twt_info.neg_type = twt_wifi_mgmt_to_rpu_neg_type(twt_params->negotiation_type);
@@ -568,7 +568,7 @@ int wifi_nrf_set_twt(const struct device *dev,
 		}
 
 		twt_info.nominal_min_twt_wake_duration =
-				twt_params->setup.twt_wake_interval_ms;
+				twt_params->setup.twt_wake_interval;
 		twt_info.twt_target_wake_interval_mantissa = twt_interval_float.mantissa;
 		twt_info.twt_target_wake_interval_exponent = twt_interval_float.exponent;
 
@@ -645,11 +645,11 @@ void wifi_nrf_event_proc_twt_setup_zep(void *vif_ctx,
 	twt_params.setup.implicit = twt_setup_info->info.is_implicit ? 1 : 0;
 	twt_params.setup.announce =
 		twt_setup_info->info.twt_flow_type == NRF_WIFI_TWT_FLOW_TYPE_ANNOUNCED;
-	twt_params.setup.twt_wake_interval_ms =
+	twt_params.setup.twt_wake_interval =
 			twt_setup_info->info.nominal_min_twt_wake_duration;
 	twt_interval_float.mantissa = twt_setup_info->info.twt_target_wake_interval_mantissa;
 	twt_interval_float.exponent = twt_setup_info->info.twt_target_wake_interval_exponent;
-	twt_params.setup.twt_interval_ms = wifi_nrf_twt_float_to_ms(twt_interval_float);
+	twt_params.setup.twt_interval = wifi_nrf_twt_float_to_ms(twt_interval_float);
 	twt_params.dialog_token = twt_setup_info->info.dialog_token;
 	twt_params.resp_status = twt_setup_info->info.twt_resp_status;
 
diff --git a/drivers/wifi/nrf700x/zephyr/src/zephyr_wifi_util.c b/drivers/wifi/nrf700x/zephyr/src/zephyr_wifi_util.c
index 3cd731183338..837214adca30 100644
--- a/drivers/wifi/nrf700x/zephyr/src/zephyr_wifi_util.c
+++ b/drivers/wifi/nrf700x/zephyr/src/zephyr_wifi_util.c
@@ -662,9 +662,8 @@ SHELL_CMD_REGISTER(wifi_util,
 		   NULL);
 
 
-static int nrf_wifi_util_init(const struct device *unused)
+static int nrf_wifi_util_init(void)
 {
-	ARG_UNUSED(unused);
 
 	if (nrf_wifi_util_conf_init(&ctx->conf_params) < 0)
 		return -1;
diff --git a/drivers/wifi/nrf700x/zephyr/src/zephyr_work.c b/drivers/wifi/nrf700x/zephyr/src/zephyr_work.c
index 5a64355d113e..d7a0bc5606f8 100644
--- a/drivers/wifi/nrf700x/zephyr/src/zephyr_work.c
+++ b/drivers/wifi/nrf700x/zephyr/src/zephyr_work.c
@@ -60,10 +60,8 @@ struct zep_work_item *work_alloc(void)
 	return &zep_work_item[free_work_index];
 }
 
-static int workqueue_init(const struct device *unused)
+static int workqueue_init(void)
 {
-	(void)unused;
-
 	k_work_queue_init(&zep_wifi_bh_q);
 
 	k_work_queue_start(&zep_wifi_bh_q,
diff --git a/ext/iperf3/iperf_util.c b/ext/iperf3/iperf_util.c
index b1668bc4499b..2f53eb6e2941 100644
--- a/ext/iperf3/iperf_util.c
+++ b/ext/iperf3/iperf_util.c
@@ -192,12 +192,12 @@ void fill_with_repeating_pattern(void *out, size_t outsize)
 void make_cookie(char *cookie)
 {
     int len = strlen(CONFIG_NRF_IPERF3_HOST_NAME);
-    char hostname[len];
+    char hostname[len + 1];
     struct timeval tv = { .tv_sec = 0, .tv_usec = 0 };
     char temp[100];
 
     /* Generate a string based on hostname, time, randomness, and filler. */
-    (void) nrf_iperf3_mock_gethostname(hostname, sizeof(hostname) + 1);    
+    (void) nrf_iperf3_mock_gethostname(hostname, sizeof(hostname));
     (void) gettimeofday(&tv, 0);
     (void) snprintf(temp, sizeof(temp), "%s.%ld.%06ld.%08lx%08lx.%s", hostname, (unsigned long int) tv.tv_sec, (unsigned long int) tv.tv_usec, (unsigned long int) rand(), (unsigned long int) rand(), "1234567890123456789012345678901234567890");
 
diff --git a/include/net/lwm2m_client_utils.h b/include/net/lwm2m_client_utils.h
index c5ed72ce7b6c..97f0a9d9ec54 100644
--- a/include/net/lwm2m_client_utils.h
+++ b/include/net/lwm2m_client_utils.h
@@ -265,7 +265,7 @@ int lwm2m_init_image(void);
  *
  * @return Zero if success, negative error code otherwise.
  */
-int lwm2m_init_connmon(const struct device *dev);
+int lwm2m_init_connmon(void);
 #endif
 
 #if defined(CONFIG_LWM2M_CLIENT_UTILS_CELL_CONN_OBJ_SUPPORT)
diff --git a/lib/at_custom_cmd/at_custom_cmd.c b/lib/at_custom_cmd/at_custom_cmd.c
index 221bfcfb20f0..6247ea840529 100644
--- a/lib/at_custom_cmd/at_custom_cmd.c
+++ b/lib/at_custom_cmd/at_custom_cmd.c
@@ -17,10 +17,8 @@
 
 LOG_MODULE_REGISTER(at_custom_cmd, CONFIG_AT_CUSTOM_CMD_LOG_LEVEL);
 
-static int at_custom_cmd_sys_init(const struct device *unused)
+static int at_custom_cmd_sys_init(void)
 {
-	(void)unused;
-
 	int err;
 	extern struct nrf_modem_at_cmd_filter _nrf_modem_at_cmd_filter_list_start[];
 	int num_items = 0;
diff --git a/lib/at_host/at_host.c b/lib/at_host/at_host.c
index cd25f1f91d04..7d0fe7c5a378 100644
--- a/lib/at_host/at_host.c
+++ b/lib/at_host/at_host.c
@@ -222,12 +222,11 @@ static int at_uart_init(const struct device *uart_dev)
 	return err;
 }
 
-static int at_host_init(const struct device *arg)
+static int at_host_init(void)
 {
 	int err;
 	enum term_modes mode = CONFIG_AT_HOST_TERMINATION;
 
-	ARG_UNUSED(arg);
 
 	/* Choosing the termination mode */
 	if (mode < MODE_COUNT) {
diff --git a/lib/at_monitor/at_monitor.c b/lib/at_monitor/at_monitor.c
index 30dc735eb040..50356a3e502e 100644
--- a/lib/at_monitor/at_monitor.c
+++ b/lib/at_monitor/at_monitor.c
@@ -103,7 +103,7 @@ static void at_monitor_task(struct k_work *work)
 	}
 }
 
-static int at_monitor_sys_init(const struct device *unused)
+static int at_monitor_sys_init(void)
 {
 	int err;
 
diff --git a/lib/date_time/date_time.c b/lib/date_time/date_time.c
index 9c1302774a53..581d30e8ef3e 100644
--- a/lib/date_time/date_time.c
+++ b/lib/date_time/date_time.c
@@ -158,7 +158,7 @@ int date_time_timestamp_clear(int64_t *unix_timestamp)
 	return 0;
 }
 
-static int date_time_init(const struct device *unused)
+static int date_time_init(void)
 {
 	date_time_core_init();
 
diff --git a/lib/flash_patch/flash_patch.c b/lib/flash_patch/flash_patch.c
index e03fb4f1eb3d..c6b97a402f9f 100644
--- a/lib/flash_patch/flash_patch.c
+++ b/lib/flash_patch/flash_patch.c
@@ -9,10 +9,8 @@
 #include <zephyr/init.h>
 
 #ifdef CONFIG_DISABLE_FLASH_PATCH
-static int disable_flash_patch(const struct device *dev)
+static int disable_flash_patch(void)
 {
-	(void)dev;
-
 	/* Check if register has been written. */
 	if ((NRF_UICR->DEBUGCTRL & UICR_DEBUGCTRL_CPUFPBEN_Msk) != 0x0) {
 		/* Enable flash write. */
diff --git a/lib/fprotect/fprotect_bprot.c b/lib/fprotect/fprotect_bprot.c
index c48346a0b41e..cf20be2c2b1b 100644
--- a/lib/fprotect/fprotect_bprot.c
+++ b/lib/fprotect/fprotect_bprot.c
@@ -22,7 +22,7 @@
 #include <errno.h>
 
  /* The number of CONFIG registers present in the chip. */
-#define BPROT_CONFIGS_NUM ceiling_fraction(BPROT_REGIONS_NUM, BITS_PER_LONG)
+#define BPROT_CONFIGS_NUM DIV_ROUND_UP(BPROT_REGIONS_NUM, BITS_PER_LONG)
 #if defined(CONFIG_SB_BPROT_IN_DEBUG)
 #define ENABLE_IN_DEBUG true
 #else
diff --git a/lib/fprotect/sys_init_fprotect.c b/lib/fprotect/sys_init_fprotect.c
index bff6bda50b97..997020f3051d 100644
--- a/lib/fprotect/sys_init_fprotect.c
+++ b/lib/fprotect/sys_init_fprotect.c
@@ -19,9 +19,8 @@ BUILD_ASSERT(PM_SIZE % CONFIG_FPROTECT_BLOCK_SIZE == 0,
 	     "Unable to protect app image since its size does not align with "
 	     "the locking granularity of fprotect.");
 
-static int fprotect_self(const struct device *dev)
+static int fprotect_self(void)
 {
-	ARG_UNUSED(dev);
 
 	int err;
 
diff --git a/lib/gcf_sms/gcf_sms.c b/lib/gcf_sms/gcf_sms.c
index ae4e3ece1d7f..552a74618fed 100644
--- a/lib/gcf_sms/gcf_sms.c
+++ b/lib/gcf_sms/gcf_sms.c
@@ -464,10 +464,8 @@ static int at_cmd_callback_cmgf(char *buf, size_t len, char *at_cmd)
 }
 
 /* Initialize the library. */
-int gcf_sms_init(const struct device *unused)
+int gcf_sms_init(void)
 {
-	(void)unused;
-
 	for (int i = 0; i < SMS_BUFFER_ARRAY_SIZE; i++) {
 		sms_buffers_clear_index(i);
 	}
diff --git a/lib/lte_link_control/lte_lc.c b/lib/lte_link_control/lte_lc.c
index 28f9c21d10d4..30996c1d79b1 100644
--- a/lib/lte_link_control/lte_lc.c
+++ b/lib/lte_link_control/lte_lc.c
@@ -719,7 +719,7 @@ static int connect_lte(bool blocking)
 	return err;
 }
 
-static int init_and_connect(const struct device *unused)
+static int init_and_connect(void)
 {
 	int err;
 
@@ -772,9 +772,7 @@ int lte_lc_connect(void)
 
 int lte_lc_init_and_connect(void)
 {
-	const struct device *x = 0;
-
-	return init_and_connect(x);
+	return init_and_connect();
 }
 
 int lte_lc_connect_async(lte_lc_evt_handler_t handler)
diff --git a/lib/nrf_modem_lib/diag.c b/lib/nrf_modem_lib/diag.c
index 3c771b71a2a6..0137c750a8a4 100644
--- a/lib/nrf_modem_lib/diag.c
+++ b/lib/nrf_modem_lib/diag.c
@@ -85,7 +85,7 @@ static void diag_task(struct k_work *item)
 }
 #endif
 
-static int nrf_modem_lib_diag_sys_init(const struct device *unused)
+static int nrf_modem_lib_diag_sys_init(void)
 {
 #if CONFIG_NRF_MODEM_LIB_MEM_DIAG_ALLOC
 	static HEAP_LISTENER_ALLOC_DEFINE(
diff --git a/lib/nrf_modem_lib/nrf91_sockets.c b/lib/nrf_modem_lib/nrf91_sockets.c
index 004c9873807f..7416e005a67c 100644
--- a/lib/nrf_modem_lib/nrf91_sockets.c
+++ b/lib/nrf_modem_lib/nrf91_sockets.c
@@ -16,6 +16,7 @@
 #include <fcntl.h>
 #include <zephyr/init.h>
 #include <zephyr/net/socket_offload.h>
+#include <zephyr/net/offloaded_netdev.h>
 #include <nrf_socket.h>
 #include <nrf_errno.h>
 #include <nrf_gai_errors.h>
@@ -1049,7 +1050,7 @@ NET_SOCKET_REGISTER(nrf91_socket, NRF91_SOCKET_PRIORITY, AF_UNSPEC,
 
 /* Create a network interface for nRF91 */
 
-static int nrf91_nrf_modem_lib_socket_offload_init(const struct device *arg)
+static int nrf91_socket_offload_init(const struct device *arg)
 {
 	ARG_UNUSED(arg);
 
@@ -1065,28 +1066,38 @@ static const struct socket_dns_offload nrf91_socket_dns_offload_ops = {
 	.freeaddrinfo = nrf91_socket_offload_freeaddrinfo,
 };
 
-static struct nrf91_socket_iface_data {
+static struct nrf91_iface_data {
 	struct net_if *iface;
-} nrf91_socket_iface_data;
+} nrf91_iface_data;
 
-static void nrf91_socket_iface_init(struct net_if *iface)
+static void nrf91_iface_api_init(struct net_if *iface)
 {
-	nrf91_socket_iface_data.iface = iface;
+	nrf91_iface_data.iface = iface;
 
 	iface->if_dev->socket_offload = nrf91_socket_create;
 
 	socket_offload_dns_register(&nrf91_socket_dns_offload_ops);
 }
 
-static struct net_if_api nrf91_if_api = {
-	.init = nrf91_socket_iface_init,
+static int nrf91_iface_enable(const struct net_if *iface, bool enabled)
+{
+	/* Enables or disable the device (in response to admin state change) */
+	ARG_UNUSED(iface);
+	ARG_UNUSED(enabled);
+
+	return 0;
+}
+
+static struct offloaded_if_api nrf91_iface_offload_api = {
+	.iface_api.init = nrf91_iface_api_init,
+	.enable = nrf91_iface_enable,
 };
 
 /* TODO Get the actual MTU for the nRF91 LTE link. */
 NET_DEVICE_OFFLOAD_INIT(nrf91_socket, "nrf91_socket",
-			nrf91_nrf_modem_lib_socket_offload_init,
+			nrf91_socket_offload_init,
 			NULL,
-			&nrf91_socket_iface_data, NULL,
-			0, &nrf91_if_api, 1280);
+			&nrf91_iface_data, NULL,
+			0, &nrf91_iface_offload_api, 1280);
 
 #endif
diff --git a/lib/nrf_modem_lib/nrf_modem_lib.c b/lib/nrf_modem_lib/nrf_modem_lib.c
index fc674c29220d..00de89692fea 100644
--- a/lib/nrf_modem_lib/nrf_modem_lib.c
+++ b/lib/nrf_modem_lib/nrf_modem_lib.c
@@ -105,7 +105,7 @@ static void log_fw_version_uuid(void)
 	}
 }
 
-static int _nrf_modem_lib_init(const struct device *unused)
+static int _nrf_modem_lib_init(void)
 {
 	int rc;
 
@@ -141,7 +141,7 @@ static int _nrf_modem_lib_init(const struct device *unused)
 
 int nrf_modem_lib_init(void)
 {
-	return _nrf_modem_lib_init(NULL);
+	return _nrf_modem_lib_init();
 }
 
 int nrf_modem_lib_bootloader_init(void)
diff --git a/lib/nrf_modem_lib/nrf_modem_os.c b/lib/nrf_modem_lib/nrf_modem_os.c
index 7243b4067a1c..583fa5bbb936 100644
--- a/lib/nrf_modem_lib/nrf_modem_os.c
+++ b/lib/nrf_modem_lib/nrf_modem_os.c
@@ -404,10 +404,8 @@ void nrf_modem_os_logdump(int level, const char *str, const void *data, size_t l
 }
 
 /* On application initialization */
-static int on_init(const struct device *dev)
+static int on_init(void)
 {
-	(void) dev;
-
 	/* The list of sleeping threads should only be initialized once at the application
 	 * initialization. This is because we want to keep the list intact regardless of modem
 	 * reinitialization to wake sleeping threads on modem initialization.
diff --git a/lib/pdn/pdn.c b/lib/pdn/pdn.c
index 064e5af9c951..d87fea8a9e06 100644
--- a/lib/pdn/pdn.c
+++ b/lib/pdn/pdn.c
@@ -539,7 +539,7 @@ static void on_cfun(enum lte_lc_func_mode mode, void *ctx)
 }
 #endif /* CONFIG_LTE_LINK_CONTROL */
 
-static int pdn_sys_init(const struct device *unused)
+static int pdn_sys_init(void)
 {
 	pdn_act_notif.cid = CID_UNASSIGNED;
 
diff --git a/lib/ram_pwrdn/ram_pwrdn.c b/lib/ram_pwrdn/ram_pwrdn.c
index 86d467095ee0..4e7875b21b83 100644
--- a/lib/ram_pwrdn/ram_pwrdn.c
+++ b/lib/ram_pwrdn/ram_pwrdn.c
@@ -217,9 +217,8 @@ static void libc_heap_resize_cb(uintptr_t heap_id, void *old_heap_end, void *new
 
 static HEAP_LISTENER_RESIZE_DEFINE(heap_listener, HEAP_ID_LIBC, libc_heap_resize_cb);
 
-static int ram_power_init(const struct device *unused)
+static int ram_power_init(void)
 {
-	ARG_UNUSED(unused);
 
 	power_down_unused_ram();
 	heap_listener_register(&heap_listener);
diff --git a/lib/st25r3911b/st25r3911b_common.h b/lib/st25r3911b/st25r3911b_common.h
index 788a6055147f..3070294ac1c0 100644
--- a/lib/st25r3911b/st25r3911b_common.h
+++ b/lib/st25r3911b/st25r3911b_common.h
@@ -65,13 +65,13 @@ enum st25r3911b_leds {
  *  using the following formula: <tt>register value * 64fc</tt>
  */
 #define ST25R3911B_FC_TO_64FC(_fc) \
-	ceiling_fraction((_fc), NFC_1FC_IN_64FC)
+	DIV_ROUND_UP((_fc), NFC_1FC_IN_64FC)
 
 /** Conversion fc to 4096/fc. The timer register can be set
  *  using the following formula: <tt>register value * 4096fc</tt>
  */
 #define ST25R3911B_FC_TO_4096FC(_fc) \
-	ceiling_fraction((_fc), NFC_1FC_IN_4096FC)
+	DIV_ROUND_UP((_fc), NFC_1FC_IN_4096FC)
 
 /** @brief Initialize the NFC reader.
  *
diff --git a/modules/memfault-firmware-sdk/memfault_integration.c b/modules/memfault-firmware-sdk/memfault_integration.c
index 7b0b31ec70e3..67dbe2c5ea30 100644
--- a/modules/memfault-firmware-sdk/memfault_integration.c
+++ b/modules/memfault-firmware-sdk/memfault_integration.c
@@ -132,11 +132,10 @@ static int device_info_init(void)
 }
 #endif /* CONFIG_MEMFAULT_NCS_DEVICE_ID_IMEI */
 
-static int init(const struct device *unused)
+static int init(void)
 {
 	int err = 0;
 
-	ARG_UNUSED(unused);
 
 	if (IS_ENABLED(CONFIG_MEMFAULT_NCS_PROVISION_CERTIFICATES)) {
 		err = memfault_zephyr_port_install_root_certs();
@@ -196,7 +195,7 @@ static void on_modem_lib_init(int ret, void *ctx)
 		return;
 	}
 
-	init(NULL);
+	init();
 }
 
 #else
diff --git a/modules/tfm/tfm/boards/src/tfm_platform_system.c b/modules/tfm/tfm/boards/src/tfm_platform_system.c
index 05d0f9f60cf6..471edc745012 100644
--- a/modules/tfm/tfm/boards/src/tfm_platform_system.c
+++ b/modules/tfm/tfm/boards/src/tfm_platform_system.c
@@ -4,8 +4,6 @@
  * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
  */
 
-#include <zephyr/sys/util.h>
-
 #include <platform/include/tfm_platform_system.h>
 #include <cmsis.h>
 #include <stdio.h>
diff --git a/samples/Kconfig b/samples/Kconfig
index c917de7bd97d..a45c5fe11a60 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -114,17 +114,6 @@ config NCS_SAMPLE_PROVISIONING_NET_CORE_CHILD_IMAGE
 
 endif # SOC_SERIES_NRF53X
 
-if LOG
-
-# LOG_DEFAULT_LEVEL is declared in Zephyr,
-# we declare it here for a second time, to set a different default.
-# Omit the `prompt` to prevent it from appearing twice in two diffent places.
-
-config LOG_DEFAULT_LEVEL
-	default 1 if NCS_SAMPLES_DEFAULTS
-
-endif # LOG
-
 menu "Image build variants"
 
 # These are set by CMake, and they need a prompt.
diff --git a/samples/app_event_manager/prj.conf b/samples/app_event_manager/prj.conf
index 943af9dfa44d..18532c366941 100644
--- a/samples/app_event_manager/prj.conf
+++ b/samples/app_event_manager/prj.conf
@@ -8,7 +8,6 @@ CONFIG_ASSERT=y
 
 # Logger configuration
 CONFIG_LOG=y
-CONFIG_LOG_DEFAULT_LEVEL=2
 CONFIG_LOG_BACKEND_UART=y
 
 # Configuration required by Application Event Manager
diff --git a/samples/app_event_manager/src/main.c b/samples/app_event_manager/src/main.c
index da99fb95e61f..19c68475bcad 100644
--- a/samples/app_event_manager/src/main.c
+++ b/samples/app_event_manager/src/main.c
@@ -14,7 +14,7 @@ LOG_MODULE_REGISTER(MODULE);
 
 #define INIT_VALUE1 3
 
-void main(void)
+int main(void)
 {
 	if (app_event_manager_init()) {
 		LOG_ERR("Application Event Manager not initialized");
@@ -24,4 +24,5 @@ void main(void)
 		event->init_value1 = INIT_VALUE1;
 		APP_EVENT_SUBMIT(event);
 	}
+	return 0;
 }
diff --git a/samples/app_event_manager_profiler_tracer/src/main.c b/samples/app_event_manager_profiler_tracer/src/main.c
index 88996046b706..c3c1e49861b3 100644
--- a/samples/app_event_manager_profiler_tracer/src/main.c
+++ b/samples/app_event_manager_profiler_tracer/src/main.c
@@ -12,7 +12,7 @@
 
 LOG_MODULE_REGISTER(MODULE);
 
-void main(void)
+int main(void)
 {
 	if (app_event_manager_init()) {
 		LOG_ERR("Application Event Manager not initialized");
@@ -21,4 +21,5 @@ void main(void)
 
 		APP_EVENT_SUBMIT(event);
 	}
+	return 0;
 }
diff --git a/samples/bluetooth/central_and_peripheral_hr/src/main.c b/samples/bluetooth/central_and_peripheral_hr/src/main.c
index 3475f5a619ac..3b436c0862a5 100644
--- a/samples/bluetooth/central_and_peripheral_hr/src/main.c
+++ b/samples/bluetooth/central_and_peripheral_hr/src/main.c
@@ -371,7 +371,7 @@ static void hrs_notify_thread(void)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 	int blink_status = 0;
@@ -381,24 +381,24 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		printk("LEDs init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_cb_register(&auth_callbacks);
 	if (err) {
 		printk("Failed to register authorization callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 	if (err) {
 		printk("Failed to register authorization info callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
-		return;
+		return 0;
 	}
 
 	if (IS_ENABLED(CONFIG_SETTINGS)) {
@@ -408,14 +408,14 @@ void main(void)
 	err = bt_hrs_client_init(&hrs_c);
 	if (err) {
 		printk("Heart Rate Service client failed to init (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	scan_init();
 
 	err = scan_start();
 	if (err) {
-		return;
+		return 0;
 	}
 
 	printk("Scanning started\n");
@@ -424,7 +424,7 @@ void main(void)
 			      sd, ARRAY_SIZE(sd));
 	if (err) {
 		printk("Advertising failed to start (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Advertising started\n");
diff --git a/samples/bluetooth/central_bas/src/main.c b/samples/bluetooth/central_bas/src/main.c
index b270de7ee8aa..86cf026640a1 100644
--- a/samples/bluetooth/central_bas/src/main.c
+++ b/samples/bluetooth/central_bas/src/main.c
@@ -361,7 +361,7 @@ static struct bt_conn_auth_info_cb conn_auth_info_callbacks = {
 };
 
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -372,7 +372,7 @@ void main(void)
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
@@ -386,26 +386,27 @@ void main(void)
 	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 	if (err) {
 		printk("Failed to register authorization callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 	if (err) {
 		printk("Failed to register authorization info callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = dk_buttons_init(button_handler);
 	if (err) {
 		printk("Failed to initialize buttons (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
 	if (err) {
 		printk("Scanning failed to start (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Scanning successfully started\n");
+	return 0;
 }
diff --git a/samples/bluetooth/central_hids/src/main.c b/samples/bluetooth/central_hids/src/main.c
index 18eeecbb3bee..123c61dabfe0 100644
--- a/samples/bluetooth/central_hids/src/main.c
+++ b/samples/bluetooth/central_hids/src/main.c
@@ -635,7 +635,7 @@ static struct bt_conn_auth_info_cb conn_auth_info_callbacks = {
 };
 
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -646,19 +646,19 @@ void main(void)
 	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 	if (err) {
 		printk("failed to register authorization callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 	if (err) {
 		printk("Failed to register authorization info callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
@@ -672,14 +672,15 @@ void main(void)
 	err = dk_buttons_init(button_handler);
 	if (err) {
 		printk("Failed to initialize buttons (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
 	if (err) {
 		printk("Scanning failed to start (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Scanning successfully started\n");
+	return 0;
 }
diff --git a/samples/bluetooth/central_hr_coded/src/main.c b/samples/bluetooth/central_hr_coded/src/main.c
index 8b1ebd2ae2b7..55614e2f3317 100644
--- a/samples/bluetooth/central_hr_coded/src/main.c
+++ b/samples/bluetooth/central_hr_coded/src/main.c
@@ -248,7 +248,7 @@ BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.disconnected = disconnected,
 };
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -257,7 +257,7 @@ void main(void)
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
@@ -265,7 +265,7 @@ void main(void)
 	err = bt_hrs_client_init(&hrs_c);
 	if (err) {
 		printk("Heart Rate Service client failed to init (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	scan_init();
@@ -273,8 +273,9 @@ void main(void)
 	err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
 	if (err) {
 		printk("Scanning failed to start (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Scanning successfully started\n");
+	return 0;
 }
diff --git a/samples/bluetooth/central_nfc_pairing/src/main.c b/samples/bluetooth/central_nfc_pairing/src/main.c
index b7f80c2bd093..33c9ac16e22a 100644
--- a/samples/bluetooth/central_nfc_pairing/src/main.c
+++ b/samples/bluetooth/central_nfc_pairing/src/main.c
@@ -313,7 +313,8 @@ static void pairing_complete(struct bt_conn *conn, bool bonded)
 	printk("Pairing completed: %s, bonded: %d\n", addr, bonded);
 
 	k_poll_signal_raise(&pair_signal, 0);
-	bt_set_oob_data_flag(false);
+	bt_le_oob_set_sc_flag(false);
+	bt_le_oob_set_legacy_flag(false);
 }
 
 
@@ -326,7 +327,8 @@ static void pairing_failed(struct bt_conn *conn, enum bt_security_err reason)
 	printk("Pairing failed conn: %s, reason %d\n", addr, reason);
 
 	k_poll_signal_raise(&pair_signal, 0);
-	bt_set_oob_data_flag(false);
+	bt_le_oob_set_sc_flag(false);
+	bt_le_oob_set_legacy_flag(false);
 }
 
 static struct bt_conn_auth_cb conn_auth_callbacks = {
@@ -409,16 +411,14 @@ static int oob_le_data_handle(const struct nfc_ndef_record_desc *rec,
 		return -EINVAL;
 	}
 
-	if (oob->le_sc_data || oob->tk_value) {
-		bt_set_oob_data_flag(true);
-	}
-
 	if (oob->le_sc_data) {
+		bt_le_oob_set_sc_flag(true);
 		oob_remote.le_sc_data = *oob->le_sc_data;
 		bt_addr_le_copy(&oob_remote.addr, oob->addr);
 	}
 
 	if (oob->tk_value) {
+		bt_le_oob_set_legacy_flag(true);
 		memcpy(remote_tk_value, oob->tk_value, sizeof(remote_tk_value));
 		use_remote_tk = request;
 	}
@@ -582,7 +582,7 @@ void button_changed(uint32_t button_state, uint32_t has_changed)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -597,7 +597,7 @@ void main(void)
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
@@ -611,18 +611,18 @@ void main(void)
 	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 	if (err) {
 		printk("Failed to register authorization callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 	if (err) {
 		printk("Failed to register authorization info callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = paring_key_generate();
 	if (err) {
-		return;
+		return 0;
 	}
 
 	err = nfc_tnep_ch_service_init(&ch_cb);
@@ -642,7 +642,7 @@ void main(void)
 		k_poll(events, ARRAY_SIZE(events), K_FOREVER);
 		err = nfc_poller_process();
 		if (err) {
-			return;
+			return 0;
 		}
 		paring_key_process();
 	}
diff --git a/samples/bluetooth/central_smp_client/src/main.c b/samples/bluetooth/central_smp_client/src/main.c
index 028a893cca57..1b44eb48f76a 100644
--- a/samples/bluetooth/central_smp_client/src/main.c
+++ b/samples/bluetooth/central_smp_client/src/main.c
@@ -425,7 +425,7 @@ static void button_handler(uint32_t button_state, uint32_t has_changed)
 }
 
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -436,7 +436,7 @@ void main(void)
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
@@ -446,14 +446,15 @@ void main(void)
 	err = dk_buttons_init(button_handler);
 	if (err) {
 		printk("Failed to initialize buttons (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
 	if (err) {
 		printk("Scanning failed to start (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Scanning successfully started\n");
+	return 0;
 }
diff --git a/samples/bluetooth/central_uart/src/main.c b/samples/bluetooth/central_uart/src/main.c
index 0ade7ea3332d..be4c1f0ae7d0 100644
--- a/samples/bluetooth/central_uart/src/main.c
+++ b/samples/bluetooth/central_uart/src/main.c
@@ -554,26 +554,26 @@ static struct bt_conn_auth_info_cb conn_auth_info_callbacks = {
 	.pairing_failed = pairing_failed
 };
 
-void main(void)
+int main(void)
 {
 	int err;
 
 	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 	if (err) {
 		LOG_ERR("Failed to register authorization callbacks.");
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 	if (err) {
 		printk("Failed to register authorization info callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		LOG_ERR("Bluetooth init failed (err %d)", err);
-		return;
+		return 0;
 	}
 	LOG_INF("Bluetooth initialized");
 
@@ -584,19 +584,19 @@ void main(void)
 	err = uart_init();
 	if (err != 0) {
 		LOG_ERR("uart_init failed (err %d)", err);
-		return;
+		return 0;
 	}
 
 	err = scan_init();
 	if (err != 0) {
 		LOG_ERR("scan_init failed (err %d)", err);
-		return;
+		return 0;
 	}
 
 	err = nus_client_init();
 	if (err != 0) {
 		LOG_ERR("nus_client_init failed (err %d)", err);
-		return;
+		return 0;
 	}
 
 	printk("Starting Bluetooth Central UART example\n");
@@ -604,7 +604,7 @@ void main(void)
 	err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
 	if (err) {
 		LOG_ERR("Scanning failed to start (err %d)", err);
-		return;
+		return 0;
 	}
 
 	LOG_INF("Scanning successfully started");
diff --git a/samples/bluetooth/direct_test_mode/src/fem/generic_fem.c b/samples/bluetooth/direct_test_mode/src/fem/generic_fem.c
index 8d71040d468c..75fda12ebe01 100644
--- a/samples/bluetooth/direct_test_mode/src/fem/generic_fem.c
+++ b/samples/bluetooth/direct_test_mode/src/fem/generic_fem.c
@@ -191,7 +191,7 @@ static const struct fem_interface_api generic_fem_api = {
 	.tx_default_gain_get = tx_default_gain_get,
 };
 
-static int generic_fem_setup(const struct device *dev)
+static int generic_fem_setup(void)
 {
 	int err;
 
diff --git a/samples/bluetooth/direct_test_mode/src/fem/nrf21540.c b/samples/bluetooth/direct_test_mode/src/fem/nrf21540.c
index 450b2e0d5130..a1efacb00423 100644
--- a/samples/bluetooth/direct_test_mode/src/fem/nrf21540.c
+++ b/samples/bluetooth/direct_test_mode/src/fem/nrf21540.c
@@ -113,7 +113,7 @@ static const struct fem_interface_api nrf21540_api = {
 	.antenna_select = nrf21540_antenna_select
 };
 
-static int nrf21540_setup(const struct device *dev)
+static int nrf21540_setup(void)
 {
 	int err;
 
diff --git a/samples/bluetooth/direct_test_mode/src/main.c b/samples/bluetooth/direct_test_mode/src/main.c
index abbd489fad9e..6237878a9aab 100644
--- a/samples/bluetooth/direct_test_mode/src/main.c
+++ b/samples/bluetooth/direct_test_mode/src/main.c
@@ -10,7 +10,7 @@
 
 #include "dtm.h"
 
-void main(void)
+int main(void)
 {
 	int err;
 	const struct device *uart = DEVICE_DT_GET(DT_CHOSEN(ncs_dtm_uart));
diff --git a/samples/bluetooth/direction_finding_central/boards/nrf52833dk_nrf52820.conf b/samples/bluetooth/direction_finding_central/boards/nrf52833dk_nrf52820.conf
index a4c80d0cd159..18a076bcfcc3 100644
--- a/samples/bluetooth/direction_finding_central/boards/nrf52833dk_nrf52820.conf
+++ b/samples/bluetooth/direction_finding_central/boards/nrf52833dk_nrf52820.conf
@@ -7,9 +7,6 @@
 CONFIG_BT_CTLR=y
 CONFIG_BT_LL_SW_SPLIT=y
 
-# Enable new implementation of LLCPs
-CONFIG_BT_LL_SW_LLCP=y
-
 # Enable Direction Finding Feature including AoA and AoD
 CONFIG_BT_CTLR_DF=y
 
diff --git a/samples/bluetooth/direction_finding_central/boards/nrf52833dk_nrf52833.conf b/samples/bluetooth/direction_finding_central/boards/nrf52833dk_nrf52833.conf
index a4c80d0cd159..18a076bcfcc3 100644
--- a/samples/bluetooth/direction_finding_central/boards/nrf52833dk_nrf52833.conf
+++ b/samples/bluetooth/direction_finding_central/boards/nrf52833dk_nrf52833.conf
@@ -7,9 +7,6 @@
 CONFIG_BT_CTLR=y
 CONFIG_BT_LL_SW_SPLIT=y
 
-# Enable new implementation of LLCPs
-CONFIG_BT_LL_SW_LLCP=y
-
 # Enable Direction Finding Feature including AoA and AoD
 CONFIG_BT_CTLR_DF=y
 
diff --git a/samples/bluetooth/direction_finding_central/child_image/hci_rpmsg.conf b/samples/bluetooth/direction_finding_central/child_image/hci_rpmsg.conf
index 42babc01a363..25c5ed07f204 100644
--- a/samples/bluetooth/direction_finding_central/child_image/hci_rpmsg.conf
+++ b/samples/bluetooth/direction_finding_central/child_image/hci_rpmsg.conf
@@ -7,9 +7,6 @@
 CONFIG_BT_CTLR=y
 CONFIG_BT_LL_SW_SPLIT=y
 
-# Enable new implementation of LLCPs
-CONFIG_BT_LL_SW_LLCP=y
-
 # Enable Direction Finding Feature including AoA and AoD
 CONFIG_BT_CTLR_DF=y
 
diff --git a/samples/bluetooth/direction_finding_central/src/main.c b/samples/bluetooth/direction_finding_central/src/main.c
index 642e31178e03..e17e88d1be79 100644
--- a/samples/bluetooth/direction_finding_central/src/main.c
+++ b/samples/bluetooth/direction_finding_central/src/main.c
@@ -1,7 +1,7 @@
 /*
  * Copyright (c) 2022 Nordic Semiconductor ASA
  *
- * SPDX-License-Identifier: Apache-2.0
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
  */
 
 #include <zephyr/types.h>
@@ -254,17 +254,18 @@ BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.cte_report_cb = cte_recv_cb,
 };
 
-void main(void)
+int main(void)
 {
 	int err;
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
 
 	start_scan();
+	return 0;
 }
diff --git a/samples/bluetooth/direction_finding_connectionless_rx/src/main.c b/samples/bluetooth/direction_finding_connectionless_rx/src/main.c
index 3546124f5908..556e2960299c 100644
--- a/samples/bluetooth/direction_finding_connectionless_rx/src/main.c
+++ b/samples/bluetooth/direction_finding_connectionless_rx/src/main.c
@@ -308,7 +308,7 @@ static void scan_disable(void)
 	scan_enabled = false;
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -333,7 +333,7 @@ void main(void)
 		err = k_sem_take(&sem_per_adv, K_FOREVER);
 		if (err) {
 			printk("failed (err %d)\n", err);
-			return;
+			return 0;
 		}
 		printk("success. Found periodic advertising.\n");
 
@@ -345,7 +345,7 @@ void main(void)
 			printk("failed (err %d)\n", err);
 			err = delete_sync();
 			if (err) {
-				return;
+				return 0;
 			}
 			continue;
 		}
@@ -360,7 +360,7 @@ void main(void)
 		err = k_sem_take(&sem_per_sync_lost, K_FOREVER);
 		if (err) {
 			printk("failed (err %d)\n", err);
-			return;
+			return 0;
 		}
 		printk("Periodic sync lost.\n");
 	}
diff --git a/samples/bluetooth/direction_finding_connectionless_tx/src/main.c b/samples/bluetooth/direction_finding_connectionless_tx/src/main.c
index ecec25528b4a..1c146555b1c0 100644
--- a/samples/bluetooth/direction_finding_connectionless_tx/src/main.c
+++ b/samples/bluetooth/direction_finding_connectionless_tx/src/main.c
@@ -75,7 +75,7 @@ static void adv_sent_cb(struct bt_le_ext_adv *adv,
 	       adv, info->num_sent);
 }
 
-void main(void)
+int main(void)
 {
 	char addr_s[BT_ADDR_LE_STR_LEN];
 	struct bt_le_oob oob_local;
@@ -88,7 +88,7 @@ void main(void)
 	err = bt_enable(NULL);
 	if (err) {
 		printk("failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 	printk("success\n");
 
@@ -96,7 +96,7 @@ void main(void)
 	err = bt_le_ext_adv_create(&param, &adv_callbacks, &adv_set);
 	if (err) {
 		printk("failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 	printk("success\n");
 
@@ -104,7 +104,7 @@ void main(void)
 	err = bt_df_set_adv_cte_tx_param(adv_set, &cte_params);
 	if (err) {
 		printk("failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 	printk("success\n");
 
@@ -112,7 +112,7 @@ void main(void)
 	err = bt_le_per_adv_set_param(adv_set, &per_adv_param);
 	if (err) {
 		printk("failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 	printk("success\n");
 
@@ -120,7 +120,7 @@ void main(void)
 	err = bt_df_adv_cte_tx_enable(adv_set);
 	if (err) {
 		printk("failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 	printk("success\n");
 
@@ -128,7 +128,7 @@ void main(void)
 	err = bt_le_per_adv_start(adv_set);
 	if (err) {
 		printk("failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 	printk("success\n");
 
@@ -136,7 +136,7 @@ void main(void)
 	err = bt_le_ext_adv_start(adv_set, &ext_adv_start_param);
 	if (err) {
 		printk("failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 	printk("success\n");
 
@@ -144,4 +144,6 @@ void main(void)
 	bt_addr_le_to_str(&oob_local.addr, addr_s, sizeof(addr_s));
 
 	printk("Started extended advertising as %s\n", addr_s);
+
+	return 0;
 }
diff --git a/samples/bluetooth/direction_finding_peripheral/boards/nrf52833dk_nrf52820.conf b/samples/bluetooth/direction_finding_peripheral/boards/nrf52833dk_nrf52820.conf
index 31c8ee5aa266..d5c5c57f3ffb 100644
--- a/samples/bluetooth/direction_finding_peripheral/boards/nrf52833dk_nrf52820.conf
+++ b/samples/bluetooth/direction_finding_peripheral/boards/nrf52833dk_nrf52820.conf
@@ -7,9 +7,6 @@
 CONFIG_BT_CTLR=y
 CONFIG_BT_LL_SW_SPLIT=y
 
-# Enable new implementation of LLCPs
-CONFIG_BT_LL_SW_LLCP=y
-
 # Enable Direction Finding Feature including AoA and AoD
 CONFIG_BT_CTLR_DF=y
 
diff --git a/samples/bluetooth/direction_finding_peripheral/boards/nrf52833dk_nrf52833.conf b/samples/bluetooth/direction_finding_peripheral/boards/nrf52833dk_nrf52833.conf
index 31c8ee5aa266..d5c5c57f3ffb 100644
--- a/samples/bluetooth/direction_finding_peripheral/boards/nrf52833dk_nrf52833.conf
+++ b/samples/bluetooth/direction_finding_peripheral/boards/nrf52833dk_nrf52833.conf
@@ -7,9 +7,6 @@
 CONFIG_BT_CTLR=y
 CONFIG_BT_LL_SW_SPLIT=y
 
-# Enable new implementation of LLCPs
-CONFIG_BT_LL_SW_LLCP=y
-
 # Enable Direction Finding Feature including AoA and AoD
 CONFIG_BT_CTLR_DF=y
 
diff --git a/samples/bluetooth/direction_finding_peripheral/child_image/hci_rpmsg.conf b/samples/bluetooth/direction_finding_peripheral/child_image/hci_rpmsg.conf
index 31c8ee5aa266..d5c5c57f3ffb 100644
--- a/samples/bluetooth/direction_finding_peripheral/child_image/hci_rpmsg.conf
+++ b/samples/bluetooth/direction_finding_peripheral/child_image/hci_rpmsg.conf
@@ -7,9 +7,6 @@
 CONFIG_BT_CTLR=y
 CONFIG_BT_LL_SW_SPLIT=y
 
-# Enable new implementation of LLCPs
-CONFIG_BT_LL_SW_LLCP=y
-
 # Enable Direction Finding Feature including AoA and AoD
 CONFIG_BT_CTLR_DF=y
 
diff --git a/samples/bluetooth/direction_finding_peripheral/src/main.c b/samples/bluetooth/direction_finding_peripheral/src/main.c
index 9a5bee7048a1..15c555f40ce4 100644
--- a/samples/bluetooth/direction_finding_peripheral/src/main.c
+++ b/samples/bluetooth/direction_finding_peripheral/src/main.c
@@ -106,15 +106,17 @@ static void bt_ready(void)
 	printk("Advertising successfully started\n");
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	bt_ready();
+
+	return 0;
 }
diff --git a/samples/bluetooth/enocean/src/main.c b/samples/bluetooth/enocean/src/main.c
index 0ffe1fc6ad19..5415885c18a5 100644
--- a/samples/bluetooth/enocean/src/main.c
+++ b/samples/bluetooth/enocean/src/main.c
@@ -110,20 +110,20 @@ static void enocean_loaded(struct bt_enocean_device *device)
 	printk("EnOcean Device loaded: %s\n", addr);
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
 	err = dk_leds_init();
 	if (err) {
 		printk("Initializing dk_leds failed (err: %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	static const struct bt_enocean_callbacks enocean_callbacks = {
@@ -143,10 +143,12 @@ void main(void)
 	err = bt_le_scan_start(BT_LE_SCAN_PASSIVE, NULL);
 	if (err) {
 		printk("Bluetooth scan start failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	bt_enocean_commissioning_enable();
 
 	printk("EnOcean sample is ready!\n");
+
+	return 0;
 }
diff --git a/samples/bluetooth/llpm/src/main.c b/samples/bluetooth/llpm/src/main.c
index 2c30dc634bed..abda26f4039f 100644
--- a/samples/bluetooth/llpm/src/main.c
+++ b/samples/bluetooth/llpm/src/main.c
@@ -420,7 +420,7 @@ BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.le_param_updated = le_param_updated,
 };
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -429,7 +429,7 @@ void main(void)
 	uint32_t dtr = 0;
 
 	if (usb_enable(NULL)) {
-		return;
+		return 0;
 	}
 
 	/* Poll if the DTR flag was set, optional */
@@ -446,7 +446,7 @@ void main(void)
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
@@ -454,18 +454,18 @@ void main(void)
 	err = bt_latency_init(&latency, NULL);
 	if (err) {
 		printk("Latency service initialization failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_latency_client_init(&latency_client, &latency_client_cb);
 	if (err) {
 		printk("Latency client initialization failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	if (enable_llpm_mode()) {
 		printk("Enable LLPM mode failed.\n");
-		return;
+		return 0;
 	}
 
 	while (true) {
@@ -491,7 +491,7 @@ void main(void)
 
 	if (enable_qos_conn_evt_report()) {
 		printk("Enable LLPM QoS failed.\n");
-		return;
+		return 0;
 	}
 
 	for (;;) {
diff --git a/samples/bluetooth/mesh/ble_peripheral_lbs_coex/src/main.c b/samples/bluetooth/mesh/ble_peripheral_lbs_coex/src/main.c
index 6fefc9a0dc2b..63d7be67ef34 100644
--- a/samples/bluetooth/mesh/ble_peripheral_lbs_coex/src/main.c
+++ b/samples/bluetooth/mesh/ble_peripheral_lbs_coex/src/main.c
@@ -46,7 +46,7 @@ static void bt_ready(int err)
 
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -56,4 +56,6 @@ void main(void)
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
 	}
+
+	return 0;
 }
diff --git a/samples/bluetooth/mesh/chat/src/main.c b/samples/bluetooth/mesh/chat/src/main.c
index 6317f43474b5..deb79d81e44b 100644
--- a/samples/bluetooth/mesh/chat/src/main.c
+++ b/samples/bluetooth/mesh/chat/src/main.c
@@ -44,7 +44,7 @@ static void bt_ready(int err)
 	printk("Mesh initialized\n");
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -54,4 +54,6 @@ void main(void)
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
 	}
+
+	return 0;
 }
diff --git a/samples/bluetooth/mesh/light/src/main.c b/samples/bluetooth/mesh/light/src/main.c
index 1879f06cece1..e84146c6dafd 100644
--- a/samples/bluetooth/mesh/light/src/main.c
+++ b/samples/bluetooth/mesh/light/src/main.c
@@ -49,7 +49,7 @@ static void bt_ready(int err)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -59,4 +59,6 @@ void main(void)
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
 	}
+
+	return 0;
 }
diff --git a/samples/bluetooth/mesh/light_ctrl/src/main.c b/samples/bluetooth/mesh/light_ctrl/src/main.c
index e6f7a4105365..c8c052a92d89 100644
--- a/samples/bluetooth/mesh/light_ctrl/src/main.c
+++ b/samples/bluetooth/mesh/light_ctrl/src/main.c
@@ -119,7 +119,7 @@ static void bt_ready(int err)
 	model_handler_start();
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -129,4 +129,6 @@ void main(void)
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
 	}
+
+	return 0;
 }
diff --git a/samples/bluetooth/mesh/light_switch/src/main.c b/samples/bluetooth/mesh/light_switch/src/main.c
index f62b118dad08..f395526a0d22 100644
--- a/samples/bluetooth/mesh/light_switch/src/main.c
+++ b/samples/bluetooth/mesh/light_switch/src/main.c
@@ -45,7 +45,7 @@ static void bt_ready(int err)
 	printk("Mesh initialized\n");
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -55,4 +55,6 @@ void main(void)
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
 	}
+
+	return 0;
 }
diff --git a/samples/bluetooth/mesh/sensor_client/src/main.c b/samples/bluetooth/mesh/sensor_client/src/main.c
index f86cc47aff3e..189a293f3ae3 100644
--- a/samples/bluetooth/mesh/sensor_client/src/main.c
+++ b/samples/bluetooth/mesh/sensor_client/src/main.c
@@ -41,7 +41,7 @@ static void bt_ready(int err)
 	printk("Mesh initialized\n");
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -51,4 +51,6 @@ void main(void)
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
 	}
+
+	return 0;
 }
diff --git a/samples/bluetooth/mesh/sensor_server/src/main.c b/samples/bluetooth/mesh/sensor_server/src/main.c
index 41e80d2d7890..21900ad9f62f 100644
--- a/samples/bluetooth/mesh/sensor_server/src/main.c
+++ b/samples/bluetooth/mesh/sensor_server/src/main.c
@@ -41,7 +41,7 @@ static void bt_ready(int err)
 	printk("Mesh initialized\n");
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -51,4 +51,6 @@ void main(void)
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
 	}
+
+	return 0;
 }
diff --git a/samples/bluetooth/mesh/silvair_enocean/src/main.c b/samples/bluetooth/mesh/silvair_enocean/src/main.c
index bab09c634351..0c5873e142e1 100644
--- a/samples/bluetooth/mesh/silvair_enocean/src/main.c
+++ b/samples/bluetooth/mesh/silvair_enocean/src/main.c
@@ -41,7 +41,7 @@ static void bt_ready(int err)
 	printk("Mesh initialized\n");
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -51,4 +51,6 @@ void main(void)
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
 	}
+
+	return 0;
 }
diff --git a/samples/bluetooth/multiple_adv_sets/src/main.c b/samples/bluetooth/multiple_adv_sets/src/main.c
index ef93fa0bfd2c..df4ab3dd4225 100644
--- a/samples/bluetooth/multiple_adv_sets/src/main.c
+++ b/samples/bluetooth/multiple_adv_sets/src/main.c
@@ -184,7 +184,7 @@ static int connectable_adv_create(void)
 	return err;
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 	int blink_status = 0;
@@ -194,27 +194,27 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		printk("LEDs init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
 
 	err = non_connectable_adv_create();
 	if (err) {
-		return;
+		return 0;
 	}
 
 	printk("Non-connectable advertising started\n");
 
 	err = connectable_adv_create();
 	if (err) {
-		return;
+		return 0;
 	}
 
 	printk("Connectable advertising started\n");
diff --git a/samples/bluetooth/nrf_dm/app.overlay b/samples/bluetooth/nrf_dm/app.overlay
index e555a1173e14..e783a7eff011 100644
--- a/samples/bluetooth/nrf_dm/app.overlay
+++ b/samples/bluetooth/nrf_dm/app.overlay
@@ -5,6 +5,11 @@
  */
 
 / {
+	/* The timer instance to use. */
+	chosen {
+		ncs,dm-timer = &timer2;
+	};
+
 	/* The selected pins will be used by Distance Measurement module for debug purposes. */
 	dm_gpio {
 		compatible = "gpio-leds";
diff --git a/samples/bluetooth/nrf_dm/src/main.c b/samples/bluetooth/nrf_dm/src/main.c
index 1ac7b3627771..fd1af7a2cc50 100644
--- a/samples/bluetooth/nrf_dm/src/main.c
+++ b/samples/bluetooth/nrf_dm/src/main.c
@@ -297,7 +297,7 @@ static struct dm_cb dm_cb = {
 	.data_ready = data_ready,
 };
 
-void main(void)
+int main(void)
 {
 	int err;
 	uint32_t blink_status = 0;
@@ -308,13 +308,13 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		printk("LEDs init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = peer_init();
 	if (err) {
 		printk("Peer init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	init_param.cb = &dm_cb;
@@ -322,25 +322,25 @@ void main(void)
 	err = dm_init(&init_param);
 	if (err) {
 		printk("Distance measurement init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = service_ddfs_init();
 	if (err) {
 		printk("DDF Service init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_sync_init();
 	if (err) {
 		printk("Synchronisation init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	for (;;) {
diff --git a/samples/bluetooth/peripheral_ams_client/src/main.c b/samples/bluetooth/peripheral_ams_client/src/main.c
index 1c9bcb7b9820..4f1d17dcf874 100644
--- a/samples/bluetooth/peripheral_ams_client/src/main.c
+++ b/samples/bluetooth/peripheral_ams_client/src/main.c
@@ -430,7 +430,7 @@ static void button_changed(uint32_t button_state, uint32_t has_changed)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int blink_status = 0;
 	int err;
@@ -440,25 +440,25 @@ void main(void)
 	err = bt_ams_client_init(&ams_c);
 	if (err) {
 		printk("AMS client init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = dk_leds_init();
 	if (err) {
 		printk("LEDs init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = dk_buttons_init(button_changed);
 	if (err) {
 		printk("Button init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("BLE init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	if (IS_ENABLED(CONFIG_SETTINGS)) {
@@ -468,19 +468,19 @@ void main(void)
 	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 	if (err) {
 		printk("Failed to register authorization callbacks\n");
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 	if (err) {
 		printk("Failed to register authorization info callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));
 	if (err) {
 		printk("Advertising failed to start (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Advertising successfully started\n");
diff --git a/samples/bluetooth/peripheral_ancs_client/src/main.c b/samples/bluetooth/peripheral_ancs_client/src/main.c
index 21dab21dc390..b0a4f2d22b5f 100644
--- a/samples/bluetooth/peripheral_ancs_client/src/main.c
+++ b/samples/bluetooth/peripheral_ancs_client/src/main.c
@@ -675,7 +675,7 @@ static void button_changed(uint32_t button_state, uint32_t has_changed)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int blink_status = 0;
 	int err;
@@ -685,31 +685,31 @@ void main(void)
 	err = ancs_c_init();
 	if (err) {
 		printk("ANCS client init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = gattp_init();
 	if (err) {
 		printk("GATT Service client init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = dk_leds_init();
 	if (err) {
 		printk("LEDs init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = dk_buttons_init(button_changed);
 	if (err) {
 		printk("Button init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("BLE init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	if (IS_ENABLED(CONFIG_SETTINGS)) {
@@ -719,19 +719,19 @@ void main(void)
 	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 	if (err) {
 		printk("Failed to register authorization callbacks\n");
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 	if (err) {
 		printk("Failed to register authorization info callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad), NULL, 0);
 	if (err) {
 		printk("Advertising failed to start (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Advertising successfully started\n");
diff --git a/samples/bluetooth/peripheral_bms/src/main.c b/samples/bluetooth/peripheral_bms/src/main.c
index a633d06f2abe..bb501b271be6 100644
--- a/samples/bluetooth/peripheral_bms/src/main.c
+++ b/samples/bluetooth/peripheral_bms/src/main.c
@@ -173,7 +173,7 @@ static int bms_init(void)
 	return bt_bms_init(&init_params);
 }
 
-void main(void)
+int main(void)
 {
 	int blink_status = 0;
 	int err;
@@ -183,25 +183,25 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		printk("LEDs init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 	if (err) {
 		printk("Failed to register authorization callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 	if (err) {
 		printk("Failed to register authorization info callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
@@ -213,14 +213,14 @@ void main(void)
 	err = bms_init();
 	if (err) {
 		printk("Failed to init BMS (err:%d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad),
 			      sd, ARRAY_SIZE(sd));
 	if (err) {
 		printk("Advertising failed to start (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Advertising successfully started\n");
diff --git a/samples/bluetooth/peripheral_cgms/src/main.c b/samples/bluetooth/peripheral_cgms/src/main.c
index 47f26faab296..a7e75835992a 100644
--- a/samples/bluetooth/peripheral_cgms/src/main.c
+++ b/samples/bluetooth/peripheral_cgms/src/main.c
@@ -103,7 +103,7 @@ static void cgms_session_state_changed(const bool state)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 	const uint8_t measurement_interval = 1; /* time in minutes. */
@@ -123,7 +123,7 @@ void main(void)
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
@@ -145,13 +145,13 @@ void main(void)
 	err = bt_cgms_init(&params);
 	if (err) {
 		printk("Error occurred when initializing cgm service (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_le_adv_start(BT_LE_ADV_CONN_NAME, ad, ARRAY_SIZE(ad), NULL, 0);
 	if (err) {
 		printk("Advertising failed to start (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Advertising successfully started\n");
diff --git a/samples/bluetooth/peripheral_cts_client/src/main.c b/samples/bluetooth/peripheral_cts_client/src/main.c
index 42ec18b74908..9f9e40896465 100644
--- a/samples/bluetooth/peripheral_cts_client/src/main.c
+++ b/samples/bluetooth/peripheral_cts_client/src/main.c
@@ -297,7 +297,7 @@ static int init_button(void)
 	return err;
 }
 
-void main(void)
+int main(void)
 {
 	int blink_status = 0;
 	int err;
@@ -307,25 +307,25 @@ void main(void)
 	err = bt_cts_client_init(&cts_c);
 	if (err) {
 		printk("CTS client init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = dk_leds_init();
 	if (err) {
 		printk("LEDs init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = init_button();
 	if (err) {
 		printk("Button init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("BLE init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	if (IS_ENABLED(CONFIG_SETTINGS)) {
@@ -335,19 +335,19 @@ void main(void)
 	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 	if (err) {
 		printk("Failed to register authorization callbacks\n");
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 	if (err) {
 		printk("Failed to register authorization info callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad), NULL, 0);
 	if (err) {
 		printk("Advertising failed to start (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Advertising successfully started\n");
diff --git a/samples/bluetooth/peripheral_fast_pair/src/main.c b/samples/bluetooth/peripheral_fast_pair/src/main.c
index 7474715c17e2..c0faf5bb8398 100644
--- a/samples/bluetooth/peripheral_fast_pair/src/main.c
+++ b/samples/bluetooth/peripheral_fast_pair/src/main.c
@@ -357,7 +357,7 @@ static void fp_account_key_written(struct bt_conn *conn)
 	LOG_INF("Fast Pair Account Key has been written");
 }
 
-void main(void)
+int main(void)
 {
 	bool run_led_on = true;
 	int err;
@@ -376,31 +376,31 @@ void main(void)
 	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 	if (err) {
 		LOG_ERR("Registering authentication callbacks failed (err %d)", err);
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_info_cb_register(&auth_info_cb);
 	if (err) {
 		LOG_ERR("Registering authentication info callbacks failed (err %d)", err);
-		return;
+		return 0;
 	}
 
 	err = bt_fast_pair_info_cb_register(&fp_info_callbacks);
 	if (err) {
 		LOG_ERR("Registering Fast Pair info callbacks failed (err %d)", err);
-		return;
+		return 0;
 	}
 
 	err = hids_helper_init();
 	if (err) {
 		LOG_ERR("HIDS init failed (err %d)", err);
-		return;
+		return 0;
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		LOG_ERR("Bluetooth init failed (err %d)", err);
-		return;
+		return 0;
 	}
 
 	LOG_INF("Bluetooth initialized");
@@ -408,7 +408,7 @@ void main(void)
 	err = settings_load();
 	if (err) {
 		LOG_ERR("Settings load failed (err: %d)", err);
-		return;
+		return 0;
 	}
 
 	LOG_INF("Settings loaded");
@@ -416,19 +416,19 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		LOG_ERR("LEDs init failed (err %d)", err);
-		return;
+		return 0;
 	}
 
 	err = battery_module_init();
 	if (err) {
 		LOG_ERR("Battery module init failed (err %d)", err);
-		return;
+		return 0;
 	}
 
 	err = bt_le_adv_prov_fast_pair_set_battery_mode(BT_FAST_PAIR_ADV_BATTERY_MODE_SHOW_UI_IND);
 	if (err) {
 		LOG_ERR("Setting advertising battery mode failed (err %d)", err);
-		return;
+		return 0;
 	}
 
 	k_work_init(&bt_adv_restart, bt_adv_restart_fn);
@@ -445,7 +445,7 @@ void main(void)
 	err = dk_buttons_init(button_changed);
 	if (err) {
 		LOG_ERR("Buttons init failed (err %d)", err);
-		return;
+		return 0;
 	}
 
 	for (;;) {
diff --git a/samples/bluetooth/peripheral_gatt_dm/src/main.c b/samples/bluetooth/peripheral_gatt_dm/src/main.c
index 765c9d512fa1..e83e7c58c32a 100644
--- a/samples/bluetooth/peripheral_gatt_dm/src/main.c
+++ b/samples/bluetooth/peripheral_gatt_dm/src/main.c
@@ -216,7 +216,7 @@ static void button_changed(uint32_t button_state, uint32_t has_changed)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -230,27 +230,29 @@ void main(void)
 	err = bt_enable(NULL);
 	if (err) {
 		printk("BLE init failed with error code %d\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 	if (err) {
 		printk("Failed to register authorization callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 	if (err) {
 		printk("Failed to register authorization info callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad),
 			      NULL, 0);
 	if (err) {
 		printk("Advertising failed to start (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Advertising successfully started\n");
+
+	return 0;
 }
diff --git a/samples/bluetooth/peripheral_hids_keyboard/src/main.c b/samples/bluetooth/peripheral_hids_keyboard/src/main.c
index 88a5b0d91b50..1921643ffe8e 100644
--- a/samples/bluetooth/peripheral_hids_keyboard/src/main.c
+++ b/samples/bluetooth/peripheral_hids_keyboard/src/main.c
@@ -931,7 +931,7 @@ static void bas_notify(void)
 }
 
 
-void main(void)
+int main(void)
 {
 	int err;
 	int blink_status = 0;
@@ -943,13 +943,13 @@ void main(void)
 	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 	if (err) {
 		printk("Failed to register authorization callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 	if (err) {
 		printk("Failed to register authorization info callbacks.\n");
-		return;
+		return 0;
 	}
 
 	hid_init();
@@ -957,7 +957,7 @@ void main(void)
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
diff --git a/samples/bluetooth/peripheral_hids_mouse/src/main.c b/samples/bluetooth/peripheral_hids_mouse/src/main.c
index 5e5f99762f06..980197bef33f 100644
--- a/samples/bluetooth/peripheral_hids_mouse/src/main.c
+++ b/samples/bluetooth/peripheral_hids_mouse/src/main.c
@@ -381,7 +381,7 @@ static void hid_init(void)
 	int err;
 	struct bt_hids_init_param hids_init_param = { 0 };
 	struct bt_hids_inp_rep *hids_inp_rep;
-	static const uint8_t mouse_movement_mask[ceiling_fraction(INPUT_REP_MOVEMENT_LEN, 8)] = {0};
+	static const uint8_t mouse_movement_mask[DIV_ROUND_UP(INPUT_REP_MOVEMENT_LEN, 8)] = {0};
 
 	static const uint8_t report_map[] = {
 		0x05, 0x01,     /* Usage Page (Generic Desktop) */
@@ -755,7 +755,7 @@ static void bas_notify(void)
 }
 
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -765,13 +765,13 @@ void main(void)
 		err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 		if (err) {
 			printk("Failed to register authorization callbacks.\n");
-			return;
+			return 0;
 		}
 
 		err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 		if (err) {
 			printk("Failed to register authorization info callbacks.\n");
-			return;
+			return 0;
 		}
 	}
 
@@ -781,7 +781,7 @@ void main(void)
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
diff --git a/samples/bluetooth/peripheral_hr_coded/src/main.c b/samples/bluetooth/peripheral_hr_coded/src/main.c
index 944657a5ea68..932b0e941c1b 100644
--- a/samples/bluetooth/peripheral_hr_coded/src/main.c
+++ b/samples/bluetooth/peripheral_hr_coded/src/main.c
@@ -166,7 +166,7 @@ static void notify_work_handler(struct k_work *work)
 	k_work_reschedule(k_work_delayable_from_work(work), K_MSEC(NOTIFY_INTERVAL));
 }
 
-void main(void)
+int main(void)
 {
 	uint32_t led_status = 0;
 	int err;
@@ -176,13 +176,13 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		printk("LEDs init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
@@ -190,7 +190,7 @@ void main(void)
 	err = create_advertising_coded();
 	if (err) {
 		printk("Advertising failed to create (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	k_work_submit(&start_advertising_worker);
diff --git a/samples/bluetooth/peripheral_lbs/src/main.c b/samples/bluetooth/peripheral_lbs/src/main.c
index 7483c69e4c97..7d8ecdffa06c 100644
--- a/samples/bluetooth/peripheral_lbs/src/main.c
+++ b/samples/bluetooth/peripheral_lbs/src/main.c
@@ -181,7 +181,7 @@ static int init_button(void)
 	return err;
 }
 
-void main(void)
+int main(void)
 {
 	int blink_status = 0;
 	int err;
@@ -191,33 +191,33 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		printk("LEDs init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = init_button();
 	if (err) {
 		printk("Button init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	if (IS_ENABLED(CONFIG_BT_LBS_SECURITY_ENABLED)) {
 		err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 		if (err) {
 			printk("Failed to register authorization callbacks.\n");
-			return;
+			return 0;
 		}
 
 		err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 		if (err) {
 			printk("Failed to register authorization info callbacks.\n");
-			return;
+			return 0;
 		}
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
@@ -229,14 +229,14 @@ void main(void)
 	err = bt_lbs_init(&lbs_callbacs);
 	if (err) {
 		printk("Failed to init LBS (err:%d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad),
 			      sd, ARRAY_SIZE(sd));
 	if (err) {
 		printk("Advertising failed to start (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Advertising successfully started\n");
diff --git a/samples/bluetooth/peripheral_mds/src/main.c b/samples/bluetooth/peripheral_mds/src/main.c
index 59982cc54df3..7ab316aaaa5d 100644
--- a/samples/bluetooth/peripheral_mds/src/main.c
+++ b/samples/bluetooth/peripheral_mds/src/main.c
@@ -274,7 +274,7 @@ static void bas_work_handler(struct k_work *work)
 	k_work_reschedule((struct k_work_delayable *)work, K_SECONDS(1));
 }
 
-void main(void)
+int main(void)
 {
 	uint32_t blink_status = 0;
 	int err;
@@ -284,37 +284,37 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		printk("LEDs init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = dk_buttons_init(button_handler);
 	if (err) {
 		printk("Failed to initialize buttons (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_mds_cb_register(&mds_cb);
 	if (err) {
 		printk("Memfault Diagnostic service callback registration failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 	if (err) {
 		printk("Failed to register authorization callbacks (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 	if (err) {
 		printk("Failed to register authorization info callbacks (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
@@ -323,7 +323,7 @@ void main(void)
 		err = settings_load();
 		if (err) {
 			printk("Failed to load settings (err %d)\n", err);
-			return;
+			return 0;
 		}
 	}
 
@@ -331,7 +331,7 @@ void main(void)
 			      sd, ARRAY_SIZE(sd));
 	if (err) {
 		printk("Advertising failed to start (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Advertising successfully started\n");
diff --git a/samples/bluetooth/peripheral_nfc_pairing/src/main.c b/samples/bluetooth/peripheral_nfc_pairing/src/main.c
index 1814ba508678..848b04a0d0f8 100644
--- a/samples/bluetooth/peripheral_nfc_pairing/src/main.c
+++ b/samples/bluetooth/peripheral_nfc_pairing/src/main.c
@@ -323,7 +323,8 @@ static void pairing_complete(struct bt_conn *conn, bool bonded)
 	printk("Pairing completed: %s, bonded: %d\n", addr, bonded);
 
 	k_poll_signal_raise(&pair_signal, 0);
-	bt_set_oob_data_flag(false);
+	bt_le_oob_set_sc_flag(false);
+	bt_le_oob_set_legacy_flag(false);
 }
 
 static void pairing_failed(struct bt_conn *conn, enum bt_security_err reason)
@@ -335,14 +336,15 @@ static void pairing_failed(struct bt_conn *conn, enum bt_security_err reason)
 	printk("Pairing failed conn: %s, reason %d\n", addr, reason);
 
 	k_poll_signal_raise(&pair_signal, 0);
-	bt_set_oob_data_flag(false);
+	bt_le_oob_set_sc_flag(false);
+	bt_le_oob_set_legacy_flag(false);
 }
 
 static enum bt_security_err pairing_accept(struct bt_conn *conn,
 				const struct bt_conn_pairing_feat *const feat)
 {
 	if (feat->oob_data_flag && (!(feat->auth_req & AUTH_SC_FLAG))) {
-		bt_set_oob_data_flag(true);
+		bt_le_oob_set_legacy_flag(true);
 	}
 
 	return BT_SECURITY_ERR_SUCCESS;
@@ -529,17 +531,14 @@ static int oob_le_data_handle(const struct nfc_ndef_record_desc *rec,
 		return -EINVAL;
 	}
 
-	if (oob->le_sc_data || oob->tk_value) {
-		bt_set_oob_data_flag(true);
-	}
-
 	if (oob->le_sc_data) {
-
+		bt_le_oob_set_sc_flag(true);
 		oob_remote.le_sc_data = *oob->le_sc_data;
 		bt_addr_le_copy(&oob_remote.addr, oob->addr);
 	}
 
 	if (oob->tk_value) {
+		bt_le_oob_set_legacy_flag(true);
 		memcpy(remote_tk_value, oob->tk_value, sizeof(remote_tk_value));
 		use_remote_tk = request;
 	}
@@ -707,7 +706,7 @@ void button_changed(uint32_t button_state, uint32_t has_changed)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -717,7 +716,7 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		printk("Cannot init LEDs!\n");
-		return;
+		return 0;
 	}
 
 	/* Configure buttons */
@@ -729,19 +728,19 @@ void main(void)
 	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 	if (err) {
 		printk("Failed to register authorization callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 	if (err) {
 		printk("Failed to register authorization info callbacks.\n");
-		return;
+		return 0;
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
@@ -752,7 +751,7 @@ void main(void)
 
 	err = paring_key_generate();
 	if (err) {
-		return;
+		return 0;
 	}
 
 	k_work_init(&adv_work, adv_handler);
diff --git a/samples/bluetooth/peripheral_power_profiling/src/main.c b/samples/bluetooth/peripheral_power_profiling/src/main.c
index 9d301fe9c394..d3d83ced03d7 100644
--- a/samples/bluetooth/peripheral_power_profiling/src/main.c
+++ b/samples/bluetooth/peripheral_power_profiling/src/main.c
@@ -652,7 +652,7 @@ static const struct bt_le_ext_adv_cb adv_callbacks = {
 	.sent = advertising_terminated
 };
 
-void main(void)
+int main(void)
 {
 	int err;
 	uint32_t blink_status = 0;
@@ -664,7 +664,7 @@ void main(void)
 	err = dk_buttons_init(button_handler);
 	if (err) {
 		printk("Failed to initialize buttons (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	/* Read the button state after booting to check if advertising start is needed. */
@@ -673,7 +673,7 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		printk("LEDs init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	reset_reason_print();
@@ -681,51 +681,51 @@ void main(void)
 	err = pwr_service_cb_register(&pwr_service_callback, NULL);
 	if (err) {
 		printk("Failed to register PWR service callback (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	if (IS_ENABLED(CONFIG_SETTINGS)) {
 		err = settings_load();
 		if (err) {
 			printk("Failed to load settings (err %d)\n", err);
-			return;
+			return 0;
 		}
 	}
 
 	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 	if (err) {
 		printk("Failed to register authorization info callbacks (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 	if (err) {
 		printk("Failed to register authorization callbacks (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_le_ext_adv_create(connectable_ad_params, &adv_callbacks, &adv_set);
 	if (err) {
 		printk("Failed to create advertising set (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = pairing_key_generate();
 	if (err) {
 		printk("Failed to generate pairing keys (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = nfc_init();
 	if (err) {
 		printk("Failed to initialize NFC (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	button_handler(button_state, has_changed);
diff --git a/samples/bluetooth/peripheral_rscs/src/main.c b/samples/bluetooth/peripheral_rscs/src/main.c
index eb159318ac10..bb0cbb55d2bf 100644
--- a/samples/bluetooth/peripheral_rscs/src/main.c
+++ b/samples/bluetooth/peripheral_rscs/src/main.c
@@ -222,7 +222,7 @@ static const struct bt_data ad[] = {
 	BT_DATA_BYTES(BT_DATA_UUID16_ALL, BT_UUID_16_ENCODE(BT_UUID_RSCS_VAL))
 };
 
-void main(void)
+int main(void)
 {
 	int err;
 	uint32_t blink_status = 0;
@@ -232,27 +232,27 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		printk("LEDs init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	if (IS_ENABLED(CONFIG_BT_RSCS_SECURITY_ENABLED)) {
 		err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 		if (err) {
 			printk("Failed to register authorization callbacks.\n");
-			return;
+			return 0;
 		}
 
 		err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 		if (err) {
 			printk("Failed to register authorization info callbacks.\n");
-			return;
+			return 0;
 		}
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
@@ -282,13 +282,13 @@ void main(void)
 	err = bt_rscs_init(&rscs_init);
 	if (err) {
 		printk("Failed to init RSCS (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = bt_le_adv_start(BT_LE_ADV_CONN_NAME, ad, ARRAY_SIZE(ad), NULL, 0);
 	if (err) {
 		printk("Advertising failed to start (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Advertising successfully started\n");
diff --git a/samples/bluetooth/peripheral_status/src/main.c b/samples/bluetooth/peripheral_status/src/main.c
index caa1e736d140..8c588f4c4d1f 100644
--- a/samples/bluetooth/peripheral_status/src/main.c
+++ b/samples/bluetooth/peripheral_status/src/main.c
@@ -172,7 +172,7 @@ static int init_button(void)
 	return err;
 }
 
-void main(void)
+int main(void)
 {
 	int blink_status = 0;
 	int err;
@@ -182,33 +182,33 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		printk("LEDs init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	err = init_button();
 	if (err) {
 		printk("Button init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	if (IS_ENABLED(CONFIG_BT_STATUS_SECURITY_ENABLED)) {
 		err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 		if (err) {
 			printk("Failed to register authorization callbacks.\n");
-			return;
+			return 0;
 		}
 
 		err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 		if (err) {
 			printk("Failed to register authorization info callbacks.\n");
-			return;
+			return 0;
 		}
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
@@ -220,7 +220,7 @@ void main(void)
 	err = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));
 	if (err) {
 		printk("Advertising failed to start (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Advertising successfully started\n");
diff --git a/samples/bluetooth/peripheral_uart/src/main.c b/samples/bluetooth/peripheral_uart/src/main.c
index 66ff5df000b2..d42e89071bdc 100644
--- a/samples/bluetooth/peripheral_uart/src/main.c
+++ b/samples/bluetooth/peripheral_uart/src/main.c
@@ -570,7 +570,7 @@ static void configure_gpio(void)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int blink_status = 0;
 	int err = 0;
@@ -586,13 +586,13 @@ void main(void)
 		err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 		if (err) {
 			printk("Failed to register authorization callbacks.\n");
-			return;
+			return 0;
 		}
 
 		err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 		if (err) {
 			printk("Failed to register authorization info callbacks.\n");
-			return;
+			return 0;
 		}
 	}
 
@@ -612,14 +612,14 @@ void main(void)
 	err = bt_nus_init(&nus_cb);
 	if (err) {
 		LOG_ERR("Failed to initialize UART service (err: %d)", err);
-		return;
+		return 0;
 	}
 
 	err = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad), sd,
 			      ARRAY_SIZE(sd));
 	if (err) {
 		LOG_ERR("Advertising failed to start (err %d)", err);
-		return;
+		return 0;
 	}
 
 	for (;;) {
diff --git a/samples/bluetooth/radio_coex_1wire/src/main.c b/samples/bluetooth/radio_coex_1wire/src/main.c
index fb3bb97fbd66..000369f022fa 100644
--- a/samples/bluetooth/radio_coex_1wire/src/main.c
+++ b/samples/bluetooth/radio_coex_1wire/src/main.c
@@ -136,13 +136,13 @@ static void setup_grant_pin(void)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	printk("Starting Radio Coex Demo 1wire on board %s\n", CONFIG_BOARD);
 
 	if (bt_enable(NULL)) {
 		printk("Bluetooth init failed");
-		return;
+		return 0;
 	}
 	printk("Bluetooth initialized\n");
 
@@ -151,7 +151,7 @@ void main(void)
 
 	if (bt_le_adv_start(BT_LE_ADV_NCONN, ad, ARRAY_SIZE(ad), NULL, 0)) {
 		printk("Advertising failed to start");
-		return;
+		return 0;
 	}
 	printk("Advertising started\n");
 
diff --git a/samples/bluetooth/rpc_host/src/main.c b/samples/bluetooth/rpc_host/src/main.c
index 12c373d3e802..ec41c6e35061 100644
--- a/samples/bluetooth/rpc_host/src/main.c
+++ b/samples/bluetooth/rpc_host/src/main.c
@@ -6,7 +6,9 @@
 
 #include <zephyr/sys/printk.h>
 
-void main(void)
+int main(void)
 {
 	printk("Starting nRF RPC bluetooth host\n");
+
+	return 0;
 }
diff --git a/samples/bluetooth/shell_bt_nus/src/main.c b/samples/bluetooth/shell_bt_nus/src/main.c
index 42adc12b3448..eb985009cee6 100644
--- a/samples/bluetooth/shell_bt_nus/src/main.c
+++ b/samples/bluetooth/shell_bt_nus/src/main.c
@@ -118,7 +118,7 @@ static struct bt_conn_auth_info_cb conn_auth_info_callbacks = {
 	.pairing_failed = pairing_failed
 };
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -128,35 +128,36 @@ void main(void)
 		err = bt_conn_auth_cb_register(&conn_auth_callbacks);
 		if (err) {
 			printk("Failed to register authorization callbacks.\n");
-			return;
+			return 0;
 		}
 
 		err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
 		if (err) {
 			printk("Failed to register authorization info callbacks.\n");
-			return;
+			return 0;
 		}
 	}
 
 	err = bt_enable(NULL);
 	if (err) {
 		LOG_ERR("BLE enable failed (err: %d)", err);
-		return;
+		return 0;
 	}
 
 	err = shell_bt_nus_init();
 	if (err) {
 		LOG_ERR("Failed to initialize BT NUS shell (err: %d)", err);
-		return;
+		return 0;
 	}
 
 	err = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad), sd,
 			      ARRAY_SIZE(sd));
 	if (err) {
 		LOG_ERR("Advertising failed to start (err %d)", err);
-		return;
+		return 0;
 	}
 
 	LOG_INF("Bluetooth ready. Advertising started.");
 
+	return 0;
 }
diff --git a/samples/bluetooth/throughput/src/main.c b/samples/bluetooth/throughput/src/main.c
index e634443737ec..9abce988a897 100644
--- a/samples/bluetooth/throughput/src/main.c
+++ b/samples/bluetooth/throughput/src/main.c
@@ -630,7 +630,7 @@ BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.le_data_len_updated = le_data_length_updated
 };
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -639,7 +639,7 @@ void main(void)
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized\n");
@@ -649,7 +649,7 @@ void main(void)
 	err = bt_throughput_init(&throughput, &throughput_cb);
 	if (err) {
 		printk("Throughput service initialization failed.\n");
-		return;
+		return 0;
 	}
 
 	printk("\n");
@@ -657,4 +657,6 @@ void main(void)
 	printk("Press button 2 or type \"peripheral\" on the peripheral board.\n");
 
 	buttons_init();
+
+	return 0;
 }
diff --git a/samples/bootloader/src/main.c b/samples/bootloader/src/main.c
index b107a0bdf7c2..02bd4d22dd90 100644
--- a/samples/bootloader/src/main.c
+++ b/samples/bootloader/src/main.c
@@ -21,10 +21,8 @@
 
 #define HUK_FLAG_OFFSET 0xFFC /* When this word is set, expect HUK to be written. */
 
-int load_huk(const struct device *unused)
+int load_huk(void)
 {
-	(void)unused;
-
 	if (!hw_unique_key_is_written(HUK_KEYSLOT_KDR)) {
 		uint32_t huk_flag_addr = PM_HW_UNIQUE_KEY_PARTITION_ADDRESS + HUK_FLAG_OFFSET;
 
@@ -109,13 +107,13 @@ static void validate_and_boot(const struct fw_info *fw_info, uint16_t slot)
 #define BOOT_SLOT_0 0
 #define BOOT_SLOT_1 1
 
-void main(void)
+int main(void)
 {
 	int err = fprotect_area(PM_B0_ADDRESS, PM_B0_SIZE);
 
 	if (err) {
 		printk("Failed to protect B0 flash, cancel startup.\n\r");
-		return;
+		return 0;
 	}
 
 	uint32_t s0_addr = s0_address_read();
@@ -132,5 +130,5 @@ void main(void)
 	}
 
 	printk("No bootable image found. Aborting boot.\n\r");
-	return;
+	return 0;
 }
diff --git a/samples/caf/src/main.c b/samples/caf/src/main.c
index 5f5cca51eb2a..6b022abfe627 100644
--- a/samples/caf/src/main.c
+++ b/samples/caf/src/main.c
@@ -12,11 +12,13 @@
 LOG_MODULE_REGISTER(MODULE);
 
 
-void main(void)
+int main(void)
 {
 	if (app_event_manager_init()) {
 		LOG_ERR("Application Event Manager not initialized");
 	} else {
 		module_set_state(MODULE_STATE_READY);
 	}
+
+	return 0;
 }
diff --git a/samples/caf_sensor_manager/remote/src/main.c b/samples/caf_sensor_manager/remote/src/main.c
index 93c01c8a3097..fb7f7553d09a 100644
--- a/samples/caf_sensor_manager/remote/src/main.c
+++ b/samples/caf_sensor_manager/remote/src/main.c
@@ -15,7 +15,7 @@
 
 LOG_MODULE_REGISTER(MODULE);
 
-void main(void)
+int main(void)
 {
 	int ret;
 
@@ -25,7 +25,7 @@ void main(void)
 	if (ret) {
 		LOG_ERR("Event Manager not initialized, err: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 	LOG_INF("Event manager initialized");
 
@@ -33,8 +33,10 @@ void main(void)
 	if (ret) {
 		LOG_ERR("Event Manager Proxy not initialized, err: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 
 	module_set_state(MODULE_STATE_READY);
+
+	return 0;
 }
diff --git a/samples/caf_sensor_manager/src/main.c b/samples/caf_sensor_manager/src/main.c
index 0dfc4764a264..341015c87066 100644
--- a/samples/caf_sensor_manager/src/main.c
+++ b/samples/caf_sensor_manager/src/main.c
@@ -16,7 +16,7 @@ LOG_MODULE_REGISTER(MODULE);
 
 #include "event_proxy_init.h"
 
-void main(void)
+int main(void)
 {
 	int ret;
 
@@ -24,7 +24,7 @@ void main(void)
 	if (ret) {
 		LOG_ERR("Event Manager not initialized, err: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 	LOG_INF("Event manager initialized");
 
@@ -32,8 +32,10 @@ void main(void)
 	if (ret) {
 		LOG_ERR("Event Manager Proxy not initialized, err: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 
 	module_set_state(MODULE_STATE_READY);
+
+	return 0;
 }
diff --git a/samples/debug/ppi_trace/Kconfig b/samples/debug/ppi_trace/Kconfig
index e6ec1f0ae051..340d3fd543f2 100644
--- a/samples/debug/ppi_trace/Kconfig
+++ b/samples/debug/ppi_trace/Kconfig
@@ -49,18 +49,6 @@ config PPI_TRACE_PIN_RADIO_ACTIVE
 
 endif # USE_BLUETOOTH_RADIO_EVENTS
 
-config USE_RTC2
-	bool
-	default y
-	depends on HAS_HW_NRF_RTC2
-	select COUNTER_RTC2
-
-config USE_RTC0
-	bool
-	default y
-	depends on !HAS_HW_NRF_RTC2
-	select COUNTER_RTC0
-
 endmenu
 
 source "Kconfig.zephyr"
diff --git a/samples/debug/ppi_trace/boards/nrf21540dk_nrf52840.overlay b/samples/debug/ppi_trace/boards/nrf21540dk_nrf52840.overlay
new file mode 100644
index 000000000000..f72dfc782f60
--- /dev/null
+++ b/samples/debug/ppi_trace/boards/nrf21540dk_nrf52840.overlay
@@ -0,0 +1,9 @@
+&rtc2 {
+	status = "okay";
+};
+
+/ {
+	zephyr,user {
+		ppi-trace-rtc = <&rtc2>;
+	};
+};
diff --git a/samples/debug/ppi_trace/boards/nrf52840dk_nrf52840.overlay b/samples/debug/ppi_trace/boards/nrf52840dk_nrf52840.overlay
index b4558783fc01..62df0e23e637 100644
--- a/samples/debug/ppi_trace/boards/nrf52840dk_nrf52840.overlay
+++ b/samples/debug/ppi_trace/boards/nrf52840dk_nrf52840.overlay
@@ -1,5 +1,12 @@
+&rtc2 {
+	status = "okay";
+};
+
 / {
         chosen {
                 zephyr,entropy = &rng;
         };
+	zephyr,user {
+		ppi-trace-rtc = <&rtc2>;
+	};
 };
diff --git a/samples/debug/ppi_trace/boards/nrf52dk_nrf52832.overlay b/samples/debug/ppi_trace/boards/nrf52dk_nrf52832.overlay
new file mode 100644
index 000000000000..f72dfc782f60
--- /dev/null
+++ b/samples/debug/ppi_trace/boards/nrf52dk_nrf52832.overlay
@@ -0,0 +1,9 @@
+&rtc2 {
+	status = "okay";
+};
+
+/ {
+	zephyr,user {
+		ppi-trace-rtc = <&rtc2>;
+	};
+};
diff --git a/samples/debug/ppi_trace/boards/nrf9160dk_nrf9160.overlay b/samples/debug/ppi_trace/boards/nrf9160dk_nrf9160.overlay
new file mode 100644
index 000000000000..fc652bf1b706
--- /dev/null
+++ b/samples/debug/ppi_trace/boards/nrf9160dk_nrf9160.overlay
@@ -0,0 +1,9 @@
+&rtc0 {
+	status = "okay";
+};
+
+/ {
+	zephyr,user {
+		ppi-trace-rtc = <&rtc0>;
+	};
+};
diff --git a/samples/debug/ppi_trace/src/main.c b/samples/debug/ppi_trace/src/main.c
index 4d717179e48b..5ab41a89ba0a 100644
--- a/samples/debug/ppi_trace/src/main.c
+++ b/samples/debug/ppi_trace/src/main.c
@@ -17,12 +17,20 @@ LOG_MODULE_REGISTER(app);
 
 #define ALARM_PERIOD_US 50000
 
-#if IS_ENABLED(CONFIG_USE_RTC2)
-#define RTC       NRF_RTC2
-#define RTC_NODE  DT_NODELABEL(rtc2)
+#define ZEPHYR_USER_NODE DT_PATH(zephyr_user)
+#if DT_NODE_HAS_PROP(ZEPHYR_USER_NODE, ppi_trace_rtc)
+#define RTC_NODE DT_PROP(ZEPHYR_USER_NODE, ppi_trace_rtc)
+#define RTC ((NRF_RTC_Type*)DT_REG_ADDR(RTC_NODE))
 #else
-#define RTC       NRF_RTC0
-#define RTC_NODE  DT_NODELABEL(rtc0)
+/*
+ * This sample now relies on the /zephyr,user node having a
+ * ppi-trace-rtc property that is a phandle to the RTC node you wish
+ * to use on your board. See the overlay files in the boards/
+ * subdirectory of this sample for examples.
+ */
+#error "Missing ppi-trace-rtc property in /zephyr,user; see source comments for details"
+#define RTC_NODE DT_INVALID_NODE
+#define RTC ((NRF_RTC_Type*)0)
 #endif
 
 static void alarm_callback(const struct device *dev, uint8_t chan_id, uint32_t ticks,
@@ -92,7 +100,7 @@ static void counter_setup(void)
 	__ASSERT_NO_MSG(err == 0);
 }
 
-void main(void)
+int main(void)
 {
 	ppi_trace_setup();
 	counter_setup();
@@ -100,4 +108,6 @@ void main(void)
 	if (IS_ENABLED(CONFIG_BT)) {
 		bluetooth_enable();
 	}
+
+	return 0;
 }
diff --git a/samples/edge_impulse/data_forwarder/src/main.c b/samples/edge_impulse/data_forwarder/src/main.c
index 7070e1a5de6e..61053d6e0571 100644
--- a/samples/edge_impulse/data_forwarder/src/main.c
+++ b/samples/edge_impulse/data_forwarder/src/main.c
@@ -106,10 +106,10 @@ static int provide_sensor_data(void)
 	return err;
 }
 
-void main(void)
+int main(void)
 {
 	if (init()) {
-		return;
+		return 0;
 	}
 	printk("Initialized\n");
 
@@ -131,4 +131,6 @@ void main(void)
 		k_sleep(K_MSEC(next_timeout - uptime));
 		next_timeout += SAMPLE_PERIOD_MS;
 	}
+
+	return 0;
 }
diff --git a/samples/edge_impulse/wrapper/src/main.c b/samples/edge_impulse/wrapper/src/main.c
index f4782aeb87ad..9f624e310c33 100644
--- a/samples/edge_impulse/wrapper/src/main.c
+++ b/samples/edge_impulse/wrapper/src/main.c
@@ -66,24 +66,24 @@ static void result_ready_cb(int err)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err = ei_wrapper_init(result_ready_cb);
 
 	if (err) {
 		printk("Edge Impulse wrapper failed to initialize (err: %d)\n",
 		       err);
-		return;
+		return 0;
 	};
 
 	if (ARRAY_SIZE(input_data) < ei_wrapper_get_window_size()) {
 		printk("Not enough input data\n");
-		return;
+		return 0;
 	}
 
 	if (ARRAY_SIZE(input_data) % ei_wrapper_get_frame_size() != 0) {
 		printk("Improper number of input samples\n");
-		return;
+		return 0;
 	}
 
 	printk("Machine learning model sampling frequency: %zu\n",
@@ -102,7 +102,7 @@ void main(void)
 	if (err) {
 		printk("Cannot provide input data (err: %d)\n", err);
 		printk("Increase CONFIG_EI_WRAPPER_DATA_BUF_SIZE\n");
-		return;
+		return 0;
 	}
 	cnt += ei_wrapper_get_window_size();
 
@@ -127,10 +127,12 @@ void main(void)
 		if (err) {
 			printk("Cannot provide input data (err: %d)\n", err);
 			printk("Increase CONFIG_EI_WRAPPER_DATA_BUF_SIZE\n");
-			return;
+			return 0;
 		}
 		cnt += ei_wrapper_get_frame_size();
 
 		k_sleep(K_MSEC(FRAME_ADD_INTERVAL_MS));
 	}
+
+	return 0;
 }
diff --git a/samples/esb/prx/src/main.c b/samples/esb/prx/src/main.c
index 69442dee8e0f..b5478307ddac 100644
--- a/samples/esb/prx/src/main.c
+++ b/samples/esb/prx/src/main.c
@@ -175,7 +175,7 @@ int esb_initialize(void)
 	return 0;
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -183,18 +183,18 @@ void main(void)
 
 	err = clocks_start();
 	if (err) {
-		return;
+		return 0;
 	}
 
 	err = leds_init();
 	if (err) {
-		return;
+		return 0;
 	}
 
 	err = esb_initialize();
 	if (err) {
 		LOG_ERR("ESB initialization failed, err %d", err);
-		return;
+		return 0;
 	}
 
 	LOG_INF("Initialization complete");
@@ -202,7 +202,7 @@ void main(void)
 	err = esb_write_payload(&tx_payload);
 	if (err) {
 		LOG_ERR("Write payload, err %d", err);
-		return;
+		return 0;
 	}
 
 	LOG_INF("Setting up for packet receiption");
@@ -210,9 +210,9 @@ void main(void)
 	err = esb_start_rx();
 	if (err) {
 		LOG_ERR("RX setup failed, err %d", err);
-		return;
+		return 0;
 	}
 
 	/* return to idle thread */
-	return;
+	return 0;
 }
diff --git a/samples/esb/ptx/src/main.c b/samples/esb/ptx/src/main.c
index df9716aeff1e..b64950ab7409 100644
--- a/samples/esb/ptx/src/main.c
+++ b/samples/esb/ptx/src/main.c
@@ -181,7 +181,7 @@ static void leds_update(uint8_t value)
 	(void)gpio_port_set_masked_raw(leds[0].port, mask, val);
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -189,18 +189,18 @@ void main(void)
 
 	err = clocks_start();
 	if (err) {
-		return;
+		return 0;
 	}
 
 	err = leds_init();
 	if (err) {
-		return;
+		return 0;
 	}
 
 	err = esb_initialize();
 	if (err) {
 		LOG_ERR("ESB initialization failed, err %d", err);
-		return;
+		return 0;
 	}
 
 	LOG_INF("Initialization complete");
diff --git a/samples/event_manager_proxy/remote/src/main.c b/samples/event_manager_proxy/remote/src/main.c
index d98ebc68fe3e..146b6469a4ad 100644
--- a/samples/event_manager_proxy/remote/src/main.c
+++ b/samples/event_manager_proxy/remote/src/main.c
@@ -18,7 +18,7 @@
 
 LOG_MODULE_REGISTER(MODULE);
 
-void main(void)
+int main(void)
 {
 	int ret;
 	const struct device *ipc_instance  = DEVICE_DT_GET(DT_NODELABEL(ipc0));
@@ -29,7 +29,7 @@ void main(void)
 	if (ret) {
 		LOG_ERR("Event Manager not initialized, err: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 	LOG_INF("Event manager initialized");
 
@@ -37,7 +37,7 @@ void main(void)
 	if (ret && ret != -EALREADY) {
 		LOG_ERR("Cannot add remote: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 	LOG_INF("Event proxy remote added");
 
@@ -46,7 +46,7 @@ void main(void)
 	if (ret) {
 		LOG_ERR("Cannot register to remote config_event: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 	LOG_INF("Event proxy config_event registered");
 
@@ -54,11 +54,13 @@ void main(void)
 	if (ret) {
 		LOG_ERR("Cannot start event manager proxy: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 
 	/* We do not have to wait for remotes here as we do not send any event that
 	 * would be fatal when missed.
 	 */
 	LOG_INF("Initialization finished successfully");
+
+	return 0;
 }
diff --git a/samples/event_manager_proxy/src/main.c b/samples/event_manager_proxy/src/main.c
index 6999d6c2128b..13514bb3d72b 100644
--- a/samples/event_manager_proxy/src/main.c
+++ b/samples/event_manager_proxy/src/main.c
@@ -22,7 +22,7 @@ LOG_MODULE_REGISTER(MODULE);
 
 #define INIT_VALUE1 3
 
-void main(void)
+int main(void)
 {
 	int ret;
 	const struct device *ipc_instance  = DEVICE_DT_GET(DT_NODELABEL(ipc0));
@@ -34,7 +34,7 @@ void main(void)
 	if (ret) {
 		LOG_ERR("Event Manager not initialized, err: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 	LOG_INF("Event manager initialized");
 
@@ -42,7 +42,7 @@ void main(void)
 	if (ret && ret != -EALREADY) {
 		LOG_ERR("Cannot add remote: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 	LOG_INF("Event proxy remote added");
 
@@ -51,14 +51,14 @@ void main(void)
 	if (ret) {
 		LOG_ERR("Cannot register to remote control_event: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 	LOG_INF("Event proxy control_event registered");
 	ret = EVENT_MANAGER_PROXY_SUBSCRIBE(ipc_instance, measurement_event);
 	if (ret) {
 		LOG_ERR("Cannot register to remote measurement_event: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 	LOG_INF("Event proxy measurement_event registered");
 
@@ -66,7 +66,7 @@ void main(void)
 	if (ret) {
 		LOG_ERR("Cannot start event manager proxy: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 	LOG_INF("Event manager proxy started");
 
@@ -75,7 +75,7 @@ void main(void)
 	if (ret) {
 		LOG_ERR("Error when waiting for remote: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 	LOG_INF("All remotes ready");
 
@@ -88,4 +88,5 @@ void main(void)
 	LOG_INF("Initialization finished successfully");
 
 	/* Main is not needed anymore - rest would be processed in events in stats module */
+	return 0;
 }
diff --git a/samples/gazell/gzll_ack_payload_device/src/main.c b/samples/gazell/gzll_ack_payload_device/src/main.c
index 0d657c9d728a..58bb7fc938bc 100644
--- a/samples/gazell/gzll_ack_payload_device/src/main.c
+++ b/samples/gazell/gzll_ack_payload_device/src/main.c
@@ -55,7 +55,7 @@ static struct k_work gzll_work;
 static void gzll_tx_result_handler(struct gzll_tx_result *tx_result);
 static void gzll_work_handler(struct k_work *work);
 
-void main(void)
+int main(void)
 {
 	int err;
 	bool result_value;
@@ -65,27 +65,27 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		LOG_ERR("Cannot initialize LEDs (err: %d)", err);
-		return;
+		return 0;
 	}
 
 	err = dk_buttons_init(NULL);
 	if (err) {
 		LOG_ERR("Cannot initialize buttons (err: %d)", err);
-		return;
+		return 0;
 	}
 
 	/* Initialize Gazell Link Layer glue */
 	result_value = gzll_glue_init();
 	if (!result_value) {
 		LOG_ERR("Cannot initialize GZLL glue code");
-		return;
+		return 0;
 	}
 
 	/* Initialize the Gazell Link Layer */
 	result_value = nrf_gzll_init(NRF_GZLL_MODE_DEVICE);
 	if (!result_value) {
 		LOG_ERR("Cannot initialize GZLL");
-		return;
+		return 0;
 	}
 
 	nrf_gzll_set_max_tx_attempts(MAX_TX_ATTEMPTS);
@@ -95,7 +95,7 @@ void main(void)
 	result_value = nrf_gzll_tx_statistics_enable(&statistics);
 	if (!result_value) {
 		LOG_ERR("Cannot enable GZLL TX statistics");
-		return;
+		return 0;
 	}
 #endif
 
@@ -104,13 +104,13 @@ void main(void)
 	result_value = nrf_gzll_add_packet_to_tx_fifo(PIPE_NUMBER, data_payload, TX_PAYLOAD_LENGTH);
 	if (!result_value) {
 		LOG_ERR("Cannot add packet to GZLL TX FIFO");
-		return;
+		return 0;
 	}
 
 	result_value = nrf_gzll_enable();
 	if (!result_value) {
 		LOG_ERR("Cannot enable GZLL");
-		return;
+		return 0;
 	}
 
 	LOG_INF("Gzll ack payload device example started.");
diff --git a/samples/gazell/gzll_ack_payload_host/src/main.c b/samples/gazell/gzll_ack_payload_host/src/main.c
index 4904f888748d..d06180e8331d 100644
--- a/samples/gazell/gzll_ack_payload_host/src/main.c
+++ b/samples/gazell/gzll_ack_payload_host/src/main.c
@@ -51,7 +51,7 @@ static struct k_work gzll_work;
 static void gzll_rx_result_handler(struct gzll_rx_result *rx_result);
 static void gzll_work_handler(struct k_work *work);
 
-void main(void)
+int main(void)
 {
 	int err;
 	bool result_value;
@@ -61,27 +61,27 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		LOG_ERR("Cannot initialize LEDs (err: %d)", err);
-		return;
+		return 0;
 	}
 
 	err = dk_buttons_init(NULL);
 	if (err) {
 		LOG_ERR("Cannot initialize buttons (err: %d)", err);
-		return;
+		return 0;
 	}
 
 	/* Initialize Gazell Link Layer glue */
 	result_value = gzll_glue_init();
 	if (!result_value) {
 		LOG_ERR("Cannot initialize GZLL glue code");
-		return;
+		return 0;
 	}
 
 	/* Initialize the Gazell Link Layer */
 	result_value = nrf_gzll_init(NRF_GZLL_MODE_HOST);
 	if (!result_value) {
 		LOG_ERR("Cannot initialize GZLL");
-		return;
+		return 0;
 	}
 
 #ifdef CONFIG_GZLL_TX_STATISTICS
@@ -89,7 +89,7 @@ void main(void)
 	result_value = nrf_gzll_tx_statistics_enable(&statistics);
 	if (!result_value) {
 		LOG_ERR("Cannot enable GZLL TX statistics");
-		return;
+		return 0;
 	}
 #endif
 
@@ -97,13 +97,13 @@ void main(void)
 	result_value = nrf_gzll_add_packet_to_tx_fifo(PIPE_NUMBER, ack_payload, TX_PAYLOAD_LENGTH);
 	if (!result_value) {
 		LOG_ERR("Cannot add packet to GZLL TX FIFO");
-		return;
+		return 0;
 	}
 
 	result_value = nrf_gzll_enable();
 	if (!result_value) {
 		LOG_ERR("Cannot enable GZLL");
-		return;
+		return 0;
 	}
 
 	LOG_INF("Gzll ack payload host example started.");
diff --git a/samples/gazell/gzp_dynamic_pairing_device/src/main.c b/samples/gazell/gzp_dynamic_pairing_device/src/main.c
index fae9c8907b3b..144b095186af 100644
--- a/samples/gazell/gzp_dynamic_pairing_device/src/main.c
+++ b/samples/gazell/gzp_dynamic_pairing_device/src/main.c
@@ -39,7 +39,7 @@ static void gzp_tx_result_checker(bool success,
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 	bool result_value;
@@ -53,7 +53,7 @@ void main(void)
 	err = dk_buttons_init(NULL);
 	if (err) {
 		LOG_ERR("Cannot initialize buttons (err: %d)", err);
-		return;
+		return 0;
 	}
 
 	settings_subsys_init();
@@ -62,14 +62,14 @@ void main(void)
 	result_value = gzll_glue_init();
 	if (!result_value) {
 		LOG_ERR("Cannot initialize GZLL glue code");
-		return;
+		return 0;
 	}
 
 	/* Initialize the Gazell Link Layer */
 	result_value = nrf_gzll_init(NRF_GZLL_MODE_DEVICE);
 	if (!result_value) {
 		LOG_ERR("Cannot initialize GZLL");
-		return;
+		return 0;
 	}
 
 	nrf_gzll_set_max_tx_attempts(MAX_TX_ATTEMPTS);
@@ -77,7 +77,7 @@ void main(void)
 	result_value = nrf_gzll_set_timeslot_period(NRF_GZLLDE_RXPERIOD_DIV_2);
 	if (!result_value) {
 		LOG_ERR("Cannot set GZLL timeslot period");
-		return;
+		return 0;
 	}
 
 	/* Erase pairing data. This sample is intended to demonstrate pairing after every reset. */
@@ -91,7 +91,7 @@ void main(void)
 	result_value = nrf_gzll_enable();
 	if (!result_value) {
 		LOG_ERR("Cannot enable GZLL");
-		return;
+		return 0;
 	}
 
 	LOG_INF("Gazell dynamic pairing example started. Device mode.");
diff --git a/samples/gazell/gzp_dynamic_pairing_host/src/main.c b/samples/gazell/gzp_dynamic_pairing_host/src/main.c
index 2f37def4dc4d..253529436611 100644
--- a/samples/gazell/gzp_dynamic_pairing_host/src/main.c
+++ b/samples/gazell/gzp_dynamic_pairing_host/src/main.c
@@ -31,7 +31,7 @@ static void led_output(uint8_t value)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	/* Debug helper variables */
 	uint32_t length;
@@ -47,27 +47,27 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		LOG_ERR("Cannot initialize LEDs (err: %d)", err);
-		return;
+		return 0;
 	}
 
 	/* Initialize Gazell Link Layer glue */
 	result_value = gzll_glue_init();
 	if (!result_value) {
 		LOG_ERR("Cannot initialize GZLL glue code");
-		return;
+		return 0;
 	}
 
 	/* Initialize the Gazell Link Layer */
 	result_value = nrf_gzll_init(NRF_GZLL_MODE_HOST);
 	if (!result_value) {
 		LOG_ERR("Cannot initialize GZLL");
-		return;
+		return 0;
 	}
 
 	result_value = nrf_gzll_set_timeslot_period(NRF_GZLLDE_RXPERIOD_DIV_2);
 	if (!result_value) {
 		LOG_ERR("Cannot set GZLL timeslot period");
-		return;
+		return 0;
 	}
 
 	/* Initialize the Gazell Pairing Library */
@@ -77,7 +77,7 @@ void main(void)
 						     (1 << UNENCRYPTED_DATA_PIPE));
 	if (!result_value) {
 		LOG_ERR("Cannot set GZLL RX pipes");
-		return;
+		return 0;
 	}
 
 	gzp_pairing_enable(true);
@@ -85,7 +85,7 @@ void main(void)
 	result_value = nrf_gzll_enable();
 	if (!result_value) {
 		LOG_ERR("Cannot enable GZLL");
-		return;
+		return 0;
 	}
 
 	LOG_INF("Gazell dynamic pairing example started. Host mode.");
diff --git a/samples/hw_id/src/main.c b/samples/hw_id/src/main.c
index 49766f64a4ab..79af94605ba4 100644
--- a/samples/hw_id/src/main.c
+++ b/samples/hw_id/src/main.c
@@ -11,7 +11,7 @@
 #include <zephyr/bluetooth/bluetooth.h>
 #endif /* defined(CONFIG_BT) */
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -27,8 +27,10 @@ void main(void)
 	err = hw_id_get(buf, ARRAY_SIZE(buf));
 	if (err) {
 		printk("hw_id_get failed (err %d)\n", err);
-		return;
+		return 0;
 	}
 
 	printk("hw_id: %s\n", buf);
+
+	return 0;
 }
diff --git a/samples/keys/hw_unique_key/src/main.c b/samples/keys/hw_unique_key/src/main.c
index e3ef74e4e536..2c9abcc70bfd 100644
--- a/samples/keys/hw_unique_key/src/main.c
+++ b/samples/keys/hw_unique_key/src/main.c
@@ -40,7 +40,7 @@ void hex_dump(uint8_t *buff, uint32_t len)
 	printk("\n");
 }
 
-void main(void)
+int main(void)
 {
 	psa_status_t status;
 	psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
@@ -59,7 +59,7 @@ void main(void)
 
 	if (result != NRF_CC3XX_PLATFORM_SUCCESS) {
 		printk("nrf_cc3xx_platform_init returned error: %d\n", result);
-		return;
+		return 0;
 	}
 
 	if (!hw_unique_key_are_any_written()) {
@@ -77,14 +77,14 @@ void main(void)
 	status = psa_crypto_init();
 	if (status != PSA_SUCCESS) {
 		printk("psa_crypto_init returned error: %d\n", status);
-		return;
+		return 0;
 	}
 
 	printk("Generating random IV\n");
 	status = psa_generate_random(iv, IV_LEN);
 	if (status != PSA_SUCCESS) {
 		printk("psa_generate_random returned error: %d\n", status);
-		return;
+		return 0;
 	}
 	printk("IV:\n");
 	hex_dump(iv, IV_LEN);
@@ -100,7 +100,7 @@ void main(void)
 
 	key_id_out = derive_key(&attributes, key_label, sizeof(key_label) - 1);
 	if (key_id_out == 0) {
-		return;
+		return 0;
 	}
 
 	printk("Key ID: 0x%x\n\n", key_id_out);
@@ -114,13 +114,15 @@ void main(void)
 				ciphertext, sizeof(ciphertext), &ciphertext_out_len);
 	if (status != PSA_SUCCESS) {
 		printk("psa_aead_encrypt returned error: %d\n", status);
-		return;
+		return 0;
 	}
 	if (ciphertext_out_len != (sizeof(plaintext) - 1 + MAC_LEN)) {
 		printk("ciphertext has wrong length: %d\n", ciphertext_out_len);
-		return;
+		return 0;
 	}
 
 	printk("Ciphertext (with authentication tag):\n");
 	hex_dump(ciphertext, ciphertext_out_len);
+
+	return 0;
 }
diff --git a/samples/keys/identity_key_generation/src/main.c b/samples/keys/identity_key_generation/src/main.c
index ba470e373267..1afd9aacb8c6 100644
--- a/samples/keys/identity_key_generation/src/main.c
+++ b/samples/keys/identity_key_generation/src/main.c
@@ -14,14 +14,14 @@
 
 LOG_MODULE_REGISTER(identity_key_generation, LOG_LEVEL_DBG);
 
-void main(void)
+int main(void)
 {
 	LOG_INF("Generating random HUK keys (including MKEK)");
 	hw_unique_key_write_random();
 
 	if (identity_key_is_written()) {
 		LOG_INF("Failure: Identity key slot already written. Exiting!");
-		return;
+		return 0;
 	}
 
 	LOG_INF("Writing the identity key to KMU");
@@ -34,8 +34,10 @@ void main(void)
 
 	if (!identity_key_is_written()) {
 		LOG_INF("Failure: Identity key is not written! Exiting!");
-		return;
+		return 0;
 	}
 
 	LOG_INF("Success!");
+
+	return 0;
 }
diff --git a/samples/keys/identity_key_usage/src/main.c b/samples/keys/identity_key_usage/src/main.c
index 71cf30750623..6dce9654b59c 100644
--- a/samples/keys/identity_key_usage/src/main.c
+++ b/samples/keys/identity_key_usage/src/main.c
@@ -20,7 +20,7 @@ uint8_t m_pub_key[IDENTITY_KEY_PUBLIC_KEY_SIZE];
 
 LOG_MODULE_REGISTER(identity_key_usage, LOG_LEVEL_DBG);
 
-void main(void)
+int main(void)
 {
 	int err;
 	psa_status_t status;
@@ -32,7 +32,7 @@ void main(void)
 	err = nrf_cc3xx_platform_init();
 	if (err != NRF_CC3XX_PLATFORM_SUCCESS) {
 		LOG_INF("nrf_cc3xx_platform_init returned error: %d", err);
-		return;
+		return 0;
 	}
 
 	LOG_INF("Initializing PSA crypto.");
@@ -40,7 +40,7 @@ void main(void)
 	status = psa_crypto_init();
 	if (status != PSA_SUCCESS) {
 		LOG_INF("psa_crypto_init returned error: %d", status);
-		return;
+		return 0;
 	}
 
 	/* Configure the key attributes for Curve type secp256r1*/
@@ -53,21 +53,21 @@ void main(void)
 
 	if (!identity_key_is_written()) {
 		LOG_INF("No identity key found in KMU (required). Exiting!");
-		return;
+		return 0;
 	}
 
 	LOG_INF("Reading the identity key.");
 	err = identity_key_read(key);
 	if (err != 0) {
 		LOG_INF("Identity key read failed! (Error: %d). Exiting!", err);
-		return;
+		return 0;
 	}
 
 	LOG_INF("Importing the identity key into PSA crypto.");
 	status = psa_import_key(&key_attributes, key, IDENTITY_KEY_SIZE_BYTES, &key_id_out);
 	if (status != PSA_SUCCESS) {
 		LOG_INF("psa_import_key failed! (Error: %d). Exiting!", status);
-		return;
+		return 0;
 	}
 
 	/* Clear out the local copy of the key to prevent leakage */
@@ -78,16 +78,18 @@ void main(void)
 
 	if (status != PSA_SUCCESS) {
 		LOG_INF("psa_export_public_key failed! (Error: %d). Exiting!", status);
-		return;
+		return 0;
 	}
 
 	if (olen != IDENTITY_KEY_PUBLIC_KEY_SIZE) {
 		LOG_INF("Output length is invalid! (Expected %d, got %d). Exiting!",
 			IDENTITY_KEY_PUBLIC_KEY_SIZE, olen);
-		return;
+		return 0;
 	}
 
 	LOG_HEXDUMP_INF(m_pub_key, IDENTITY_KEY_PUBLIC_KEY_SIZE, "Public key:");
 
 	LOG_INF("Success!");
+
+	return 0;
 }
diff --git a/samples/keys/random_hw_unique_key/src/main.c b/samples/keys/random_hw_unique_key/src/main.c
index b6e6fa84ed0d..572703a3ac4b 100644
--- a/samples/keys/random_hw_unique_key/src/main.c
+++ b/samples/keys/random_hw_unique_key/src/main.c
@@ -10,9 +10,11 @@
 #include <stdio.h>
 #include <hw_unique_key.h>
 
-void main(void)
+int main(void)
 {
 	printk("Writing random keys to KMU.\n\r");
 	hw_unique_key_write_random();
 	printk("Success!\n\r");
+
+	return 0;
 }
diff --git a/samples/mpsl/timeslot/src/main.c b/samples/mpsl/timeslot/src/main.c
index 3a875e1c26d2..8be64d6f2ad2 100644
--- a/samples/mpsl/timeslot/src/main.c
+++ b/samples/mpsl/timeslot/src/main.c
@@ -280,7 +280,7 @@ static void mpsl_nonpreemptible_thread(void)
 	}
 }
 
-void main(void)
+int main(void)
 {
 
 	int err = console_init();
diff --git a/samples/nfc/system_off/src/main.c b/samples/nfc/system_off/src/main.c
index 304575d3b2d3..a4971194b07f 100644
--- a/samples/nfc/system_off/src/main.c
+++ b/samples/nfc/system_off/src/main.c
@@ -202,12 +202,12 @@ static void print_reset_reason(void)
 }
 
 
-void main(void)
+int main(void)
 {
 	/* Configure LED-pins */
 	if (dk_leds_init() < 0) {
 		printk("Cannot init LEDs!\n");
-		return;
+		return 0;
 	}
 	dk_set_led_on(SYSTEM_ON_LED);
 
@@ -221,11 +221,12 @@ void main(void)
 	/* Start NFC */
 	if (start_nfc() < 0) {
 		printk("ERROR: NFC configuration failed\n");
-		return;
+		return 0;
 	}
 
 	/* Prevent deep sleep (system off) from being entered */
 	pm_policy_state_lock_get(PM_STATE_SOFT_OFF, PM_ALL_SUBSTATES);
 
 	/* Exit main function - the rest will be done by the callbacks */
+	return 0;
 }
diff --git a/samples/nfc/tag_reader/src/main.c b/samples/nfc/tag_reader/src/main.c
index 0e53fc4066e8..5ad5d7606378 100644
--- a/samples/nfc/tag_reader/src/main.c
+++ b/samples/nfc/tag_reader/src/main.c
@@ -682,7 +682,7 @@ static const struct nfc_t4t_hl_procedure_cb t4t_hl_procedure_cb = {
 	.ndef_read = t4t_hl_ndef_read
 };
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -697,19 +697,19 @@ void main(void)
 	if (err) {
 		printk("NFC T4T ISO-DEP Protocol initialization failed err: %d.\n",
 		       err);
-		return;
+		return 0;
 	}
 
 	err = st25r3911b_nfca_init(events, ARRAY_SIZE(events), &cb);
 	if (err) {
 		printk("NFCA initialization failed err: %d.\n", err);
-		return;
+		return 0;
 	}
 
 	err = st25r3911b_nfca_field_on();
 	if (err) {
 		printk("Field on error %d.", err);
-		return;
+		return 0;
 	}
 
 	while (true) {
@@ -717,7 +717,7 @@ void main(void)
 		err = st25r3911b_nfca_process();
 		if (err) {
 			printk("NFC-A process failed, err: %d.\n", err);
-			return;
+			return 0;
 		}
 	}
 }
diff --git a/samples/nfc/tnep_poller/src/main.c b/samples/nfc/tnep_poller/src/main.c
index c3d36f6de652..e2ce16a22fc8 100644
--- a/samples/nfc/tnep_poller/src/main.c
+++ b/samples/nfc/tnep_poller/src/main.c
@@ -652,7 +652,7 @@ static struct nfc_tnep_poller_cb tnep_cb = {
 	.error = tnep_error
 };
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -666,7 +666,7 @@ void main(void)
 	err = nfc_tnep_poller_init(&tnep_tx_buf);
 	if (err) {
 		printk("NFC TNEP Protocol initialization err: %d\n", err);
-		return;
+		return 0;
 	}
 
 	err = nfc_t4t_isodep_init(tx_data, sizeof(tx_data),
@@ -675,19 +675,19 @@ void main(void)
 	if (err) {
 		printk("NFC T4T ISO-DEP Protocol initialization failed err: %d.\n",
 		       err);
-		return;
+		return 0;
 	}
 
 	err = st25r3911b_nfca_init(events, ARRAY_SIZE(events), &cb);
 	if (err) {
 		printk("NFCA initialization failed err: %d.\n", err);
-		return;
+		return 0;
 	}
 
 	err = st25r3911b_nfca_field_on();
 	if (err) {
 		printk("Field on error %d.", err);
-		return;
+		return 0;
 	}
 
 	while (true) {
@@ -695,7 +695,7 @@ void main(void)
 		err = st25r3911b_nfca_process();
 		if (err) {
 			printk("NFC-A process failed, err: %d.\n", err);
-			return;
+			return 0;
 		}
 	}
 }
diff --git a/samples/nfc/tnep_tag/src/main.c b/samples/nfc/tnep_tag/src/main.c
index d2f20fd81409..b175255c7294 100644
--- a/samples/nfc/tnep_tag/src/main.c
+++ b/samples/nfc/tnep_tag/src/main.c
@@ -183,7 +183,7 @@ static void button_pressed(uint32_t button_state, uint32_t has_changed)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -192,13 +192,13 @@ void main(void)
 	err = dk_leds_init();
 	if (err) {
 		printk("led init error %d", err);
-		return;
+		return 0;
 	}
 
 	err = dk_buttons_init(button_pressed);
 	if (err) {
 		printk("buttons init error %d", err);
-		return;
+		return 0;
 	}
 
 	/* TNEP init */
@@ -206,21 +206,21 @@ void main(void)
 						  sizeof(tag_buffer));
 	if (err) {
 		printk("Cannot register tnep buffer, err: %d\n", err);
-		return;
+		return 0;
 	}
 
 	err = nfc_tnep_tag_init(events, ARRAY_SIZE(events),
 				nfc_t4t_ndef_rwpayload_set);
 	if (err) {
 		printk("Cannot initialize TNEP protocol, err: %d\n", err);
-		return;
+		return 0;
 	}
 
 	/* Type 4 Tag setup */
 	err = nfc_t4t_setup(nfc_callback, NULL);
 	if (err) {
 		printk("NFC T4T setup err: %d\n", err);
-		return;
+		return 0;
 	}
 
 /** .. include_startingpoint_initial_msg_rst */
@@ -234,7 +234,7 @@ void main(void)
 	err = nfc_t4t_emulation_start();
 	if (err) {
 		printk("NFC T4T emulation start err: %d\n", err);
-		return;
+		return 0;
 	}
 
 	dk_set_led_on(LED_INIT);
diff --git a/samples/nrf5340/empty_app_core/src/main.c b/samples/nrf5340/empty_app_core/src/main.c
index 5a0aff0dca41..df490a7a8e35 100644
--- a/samples/nrf5340/empty_app_core/src/main.c
+++ b/samples/nrf5340/empty_app_core/src/main.c
@@ -36,11 +36,13 @@ void disable_ram_and_wfi(register volatile uint32_t *reg_begin,
 	} while (1);
 }
 
-void main(void)
+int main(void)
 {
 	/* Power off RAM and suspend CPU */
 	disable_ram_and_wfi(&NRF_VMC->RAM[0].POWER,
 			    &NRF_VMC->RAM[ARRAY_SIZE(NRF_VMC->RAM) - 1].POWER);
+
+	return 0;
 }
 
 /** @brief Allow access to specific GPIOs for the network core.
@@ -49,9 +51,8 @@ void main(void)
  * that the network core is not started yet. More pins can be added if the
  * network core needs them.
  */
-static int network_gpio_allow(const struct device *dev)
+static int network_gpio_allow(void)
 {
-	ARG_UNUSED(dev);
 
 	/* When the use of the low frequency crystal oscillator (LFXO) is
 	 * enabled, do not modify the configuration of the pins P0.00 (XL1)
diff --git a/samples/nrf5340/empty_net_core/prj.conf b/samples/nrf5340/empty_net_core/prj.conf
new file mode 100644
index 000000000000..bb7b160deb37
--- /dev/null
+++ b/samples/nrf5340/empty_net_core/prj.conf
@@ -0,0 +1 @@
+# Intentionally empty
diff --git a/samples/nrf5340/empty_net_core/src/main.c b/samples/nrf5340/empty_net_core/src/main.c
index 545f08bfbc4a..569945d796b1 100644
--- a/samples/nrf5340/empty_net_core/src/main.c
+++ b/samples/nrf5340/empty_net_core/src/main.c
@@ -6,7 +6,7 @@
 
 #include <zephyr/kernel.h>
 
-void main(void)
+int main(void)
 {
-	; /* Dummy application. Unused main */
+	return 0; /* Dummy application. Unused main */
 }
diff --git a/samples/nrf5340/multiprotocol_rpmsg/src/main.c b/samples/nrf5340/multiprotocol_rpmsg/src/main.c
index 3e47b12826bd..279d15812201 100644
--- a/samples/nrf5340/multiprotocol_rpmsg/src/main.c
+++ b/samples/nrf5340/multiprotocol_rpmsg/src/main.c
@@ -1,7 +1,7 @@
 /*
  * Copyright (c) 2019-2021 Nordic Semiconductor ASA
  *
- * SPDX-License-Identifier: Apache-2.0
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
  */
 
 #include <errno.h>
@@ -216,7 +216,7 @@ static struct ipc_ept_cfg hci_ept_cfg = {
 	},
 };
 
-void main(void)
+int main(void)
 {
 	int err;
 	const struct device *hci_ipc_instance = DEVICE_DT_GET(DT_NODELABEL(ipc0));
diff --git a/samples/nrf5340/netboot/src/main.c b/samples/nrf5340/netboot/src/main.c
index 10b2471aed74..b6b3326e3910 100644
--- a/samples/nrf5340/netboot/src/main.c
+++ b/samples/nrf5340/netboot/src/main.c
@@ -16,14 +16,14 @@
 #include <zephyr/device.h>
 #include <zephyr/devicetree.h>
 
-void main(void)
+int main(void)
 {
 	int err;
 	const struct device *fdev = DEVICE_DT_GET(DT_CHOSEN(zephyr_flash_controller));
 
 	if (!device_is_ready(fdev)) {
 		printk("Flash device not ready\n");
-		return;
+		return 0;
 	}
 
 	/* The flash is locked at flash page granularity */
@@ -86,8 +86,9 @@ void main(void)
 	}
 
 	bl_boot(fw_info_find(s0_addr));
-	return;
+	return 0;
 
 failure:
 	pcd_fw_copy_invalidate();
+	return 0;
 }
diff --git a/samples/nrf5340/remote_shell/src/main.c b/samples/nrf5340/remote_shell/src/main.c
index 0ebe49e0a5ed..b7ad0b73cc74 100644
--- a/samples/nrf5340/remote_shell/src/main.c
+++ b/samples/nrf5340/remote_shell/src/main.c
@@ -128,7 +128,7 @@ static void uart_irq_handler(const struct device *dev, void *user_data)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 	const struct device *dev = DEVICE_DT_GET(DT_CHOSEN(ncs_remote_shell_uart));
@@ -136,14 +136,14 @@ void main(void)
 
 	if (!device_is_ready(dev)) {
 		LOG_ERR("Device not ready");
-		return;
+		return 0;
 	}
 
 	if (IS_ENABLED(CONFIG_USB_DEVICE_STACK)) {
 		err = usb_enable(NULL);
 		if (err != 0) {
 			LOG_ERR("Failed to enable USB, err %d", err);
-			return;
+			return 0;
 		}
 	}
 
@@ -184,7 +184,7 @@ void main(void)
 	err = shell_ipc_host_init(ipc_host_receive, (void *)dev);
 	if (err) {
 		LOG_ERR("Shell IPC host initialization failed, err %d", err);
-		return;
+		return 0;
 	}
 
 	for (;;) {
diff --git a/samples/nrf9160/at_client/src/main.c b/samples/nrf9160/at_client/src/main.c
index 33a50129fa58..f4b567e67013 100644
--- a/samples/nrf9160/at_client/src/main.c
+++ b/samples/nrf9160/at_client/src/main.c
@@ -23,7 +23,7 @@ void enable_xtal(void)
 	(void)onoff_request(clk_mgr, &cli);
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -32,8 +32,10 @@ void main(void)
 	err = nrf_modem_lib_init();
 	if (err) {
 		printk("Modem library initialization failed, error: %d\n", err);
-		return;
+		return 0;
 	}
 	enable_xtal();
 	printk("Ready\n");
+
+	return 0;
 }
diff --git a/samples/nrf9160/at_monitor/src/main.c b/samples/nrf9160/at_monitor/src/main.c
index 177e9664ef51..1d3fe9a2f7ac 100644
--- a/samples/nrf9160/at_monitor/src/main.c
+++ b/samples/nrf9160/at_monitor/src/main.c
@@ -131,7 +131,7 @@ static void psm_read(void)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -140,27 +140,27 @@ void main(void)
 	err = nrf_modem_lib_init();
 	if (err) {
 		printk("Modem library initialization failed, error: %d\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Subscribing to notifications\n");
 	err = nrf_modem_at_printf("AT+CEREG=1");
 	if (err) {
 		printk("AT+CEREG failed\n");
-		return;
+		return 0;
 	}
 
 	err = nrf_modem_at_printf("AT%%CESQ=1");
 	if (err) {
 		printk("AT+CESQ failed\n");
-		return;
+		return 0;
 	}
 
 	printk("Connecting to network\n");
 	err = nrf_modem_at_printf("AT+CFUN=1");
 	if (err) {
 		printk("AT+CFUN failed\n");
-		return;
+		return 0;
 	}
 
 	/* Let's monitor link quality while attempting to register to network */
@@ -189,7 +189,7 @@ void main(void)
 	err = psm_control(ENABLE);
 	if (err) {
 		printk("Could not enable power saving mode\n");
-		return;
+		return 0;
 	}
 
 	psm_read();
@@ -197,7 +197,7 @@ void main(void)
 	err = nrf_modem_at_cmd(response, sizeof(response), "AT+CEREG?");
 	if (err) {
 		printk("Failed to read CEREG, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Modem response:\n%s", response);
@@ -206,8 +206,9 @@ void main(void)
 	err = nrf_modem_at_printf("AT+CFUN=0");
 	if (err) {
 		printk("AT+CFUN failed\n");
-		return;
+		return 0;
 	}
 	nrf_modem_lib_shutdown();
 	printk("Bye\n");
+	return 0;
 }
diff --git a/samples/nrf9160/aws_iot/src/main.c b/samples/nrf9160/aws_iot/src/main.c
index b86eea006993..7b80e8a56dfa 100644
--- a/samples/nrf9160/aws_iot/src/main.c
+++ b/samples/nrf9160/aws_iot/src/main.c
@@ -466,7 +466,7 @@ static void date_time_event_handler(const struct date_time_evt *evt)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -478,7 +478,7 @@ void main(void)
 	err = nrf_modem_lib_init();
 	if (err) {
 		LOG_ERR("Modem library initialization failed, error: %d", err);
-		return;
+		return 0;
 	}
 
 	nrf_modem_lib_dfu_handler(err);
@@ -490,7 +490,7 @@ void main(void)
 	err = hw_id_get(device_id, ARRAY_SIZE(device_id));
 	if (err) {
 		LOG_ERR("Failed to retrieve device ID, error: %d", err);
-		return;
+		return 0;
 	}
 
 	struct aws_iot_config config = {
@@ -521,7 +521,7 @@ void main(void)
 	err = lte_lc_init_and_connect_async(lte_handler);
 	if (err) {
 		LOG_ERR("Modem could not be configured, error: %d", err);
-		return;
+		return 0;
 	}
 
 	err = modem_info_init();
@@ -540,4 +540,6 @@ void main(void)
 	/* Postpone connecting to AWS IoT until date time has been obtained. */
 	k_sem_take(&date_time_obtained, K_FOREVER);
 	k_work_schedule(&connect_work, K_NO_WAIT);
+
+	return 0;
 }
diff --git a/samples/nrf9160/azure_fota/src/main.c b/samples/nrf9160/azure_fota/src/main.c
index 1ef9a3a58e52..e4eaaf3d6aff 100644
--- a/samples/nrf9160/azure_fota/src/main.c
+++ b/samples/nrf9160/azure_fota/src/main.c
@@ -190,7 +190,7 @@ static void modem_configure(void)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -222,7 +222,7 @@ void main(void)
 	case -1:
 		LOG_INF("Could not initialize modem library");
 		LOG_INF("Fatal error.");
-		return;
+		return 0;
 	default:
 		break;
 	}
@@ -233,7 +233,7 @@ void main(void)
 	if (err) {
 		LOG_ERR("Azure IoT Hub could not be initialized, error: %d",
 		       err);
-		return;
+		return 0;
 	}
 
 	LOG_INF("Connecting to LTE network");
@@ -246,7 +246,7 @@ void main(void)
 	err = hw_id_get(device_id, ARRAY_SIZE(device_id));
 	if (err) {
 		LOG_ERR("Failed to retrieve device ID");
-		return;
+		return 0;
 	}
 #endif
 
@@ -264,7 +264,7 @@ void main(void)
 	err = azure_iot_hub_connect(&config);
 	if (err < 0) {
 		LOG_ERR("azure_iot_hub_connect failed: %d", err);
-		return;
+		return 0;
 	}
 
 	k_sem_take(&cloud_connected_sem, K_FOREVER);
@@ -273,4 +273,6 @@ void main(void)
 	 * image as working so that we will not revert upon reboot.
 	 */
 	boot_write_img_confirmed();
+
+	return 0;
 }
diff --git a/samples/nrf9160/azure_iot_hub/src/main.c b/samples/nrf9160/azure_iot_hub/src/main.c
index f29db57d0047..6a90f33b5cee 100644
--- a/samples/nrf9160/azure_iot_hub/src/main.c
+++ b/samples/nrf9160/azure_iot_hub/src/main.c
@@ -528,7 +528,7 @@ static int dps_run(struct azure_iot_hub_buf *hostname, struct azure_iot_hub_buf
 }
 #endif /* CONFIG_AZURE_IOT_HUB_DPS */
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -538,7 +538,7 @@ void main(void)
 	err = hw_id_get(device_id, ARRAY_SIZE(device_id));
 	if (err) {
 		LOG_ERR("Failed to retrieve device ID");
-		return;
+		return 0;
 	}
 #else
 	char device_id[128] = CONFIG_AZURE_IOT_HUB_DEVICE_ID;
@@ -564,7 +564,7 @@ void main(void)
 	err = nrf_modem_lib_init();
 	if (err) {
 		LOG_ERR("Modem library initialization failed, error: %d", err);
-		return;
+		return 0;
 	}
 #endif
 
@@ -587,14 +587,14 @@ void main(void)
 	err = dps_run(&cfg.hostname, &cfg.device_id);
 	if (err) {
 		LOG_ERR("Failed to run DPS, error: %d, terminating connection attempt", err);
-		return;
+		return 0;
 	}
 #endif
 
 	err = azure_iot_hub_init(azure_event_handler);
 	if (err) {
 		LOG_ERR("Azure IoT Hub could not be initialized, error: %d", err);
-		return;
+		return 0;
 	}
 
 	LOG_INF("Azure IoT Hub library initialized");
@@ -602,7 +602,7 @@ void main(void)
 	err = azure_iot_hub_connect(&cfg);
 	if (err < 0) {
 		LOG_ERR("azure_iot_hub_connect failed: %d", err);
-		return;
+		return 0;
 	}
 
 	LOG_INF("Connection request sent to IoT Hub");
@@ -612,4 +612,5 @@ void main(void)
 	 * See azure_event_handler() for which actions will be taken on the
 	 * various events.
 	 */
+	return 0;
 }
diff --git a/samples/nrf9160/ciphersuites/src/main.c b/samples/nrf9160/ciphersuites/src/main.c
index 58819be62017..26f405883450 100644
--- a/samples/nrf9160/ciphersuites/src/main.c
+++ b/samples/nrf9160/ciphersuites/src/main.c
@@ -136,7 +136,7 @@ int tls_setup(int fd)
 	return 0;
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 	int fd;
@@ -152,27 +152,27 @@ void main(void)
 	err = nrf_modem_lib_init();
 	if (err) {
 		printk("Modem library initialization failed, error: %d\n", err);
-		return;
+		return 0;
 	}
 
 	/* Provision certificates before connecting to the LTE network */
 	err = cert_provision();
 	if (err) {
-		return;
+		return 0;
 	}
 
 	printk("Waiting for network.. ");
 	err = lte_lc_init_and_connect();
 	if (err) {
 		printk("Failed to connect to the LTE network, err %d\n", err);
-		return;
+		return 0;
 	}
 	printk("OK\n");
 
 	err = getaddrinfo(HTTPS_HOSTNAME, NULL, &hints, &res);
 	if (err) {
 		printk("getaddrinfo() failed, err %d, %s\n", errno, strerror(errno));
-		return;
+		return 0;
 	}
 
 	((struct sockaddr_in *)res->ai_addr)->sin_port = htons(HTTPS_PORT);
@@ -233,4 +233,6 @@ void main(void)
 	(void)close(fd);
 
 	lte_lc_power_off();
+
+	return 0;
 }
diff --git a/samples/nrf9160/coap_client/src/main.c b/samples/nrf9160/coap_client/src/main.c
index 8c4441c6f5d6..ff63f6601a55 100644
--- a/samples/nrf9160/coap_client/src/main.c
+++ b/samples/nrf9160/coap_client/src/main.c
@@ -220,7 +220,7 @@ static int wait(int timeout)
 	return 0;
 }
 
-void main(void)
+int main(void)
 {
 	int64_t next_msg_time = APP_COAP_SEND_INTERVAL_MS;
 	int err, received;
@@ -230,19 +230,19 @@ void main(void)
 	err = nrf_modem_lib_init();
 	if (err) {
 		printk("Modem library initialization failed, error: %d\n", err);
-		return;
+		return 0;
 	}
 
 	modem_configure();
 
 	if (server_resolve() != 0) {
 		printk("Failed to resolve server name\n");
-		return;
+		return 0;
 	}
 
 	if (client_init() != 0) {
 		printk("Failed to initialize CoAP client\n");
-		return;
+		return 0;
 	}
 
 	next_msg_time = k_uptime_get();
@@ -297,4 +297,6 @@ void main(void)
 	}
 
 	(void)close(sock);
+
+	return 0;
 }
diff --git a/samples/nrf9160/download/src/main.c b/samples/nrf9160/download/src/main.c
index ae32d6cfa533..560bf2443cd5 100644
--- a/samples/nrf9160/download/src/main.c
+++ b/samples/nrf9160/download/src/main.c
@@ -169,7 +169,7 @@ static int callback(const struct download_client_evt *event)
 	return 0;
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -178,14 +178,14 @@ void main(void)
 	err = nrf_modem_lib_init();
 	if (err) {
 		printk("Modem library initialization failed, error: %d\n", err);
-		return;
+		return 0;
 	}
 
 #if CONFIG_SAMPLE_SECURE_SOCKET
 	/* Provision certificates before connecting to the network */
 	err = cert_provision();
 	if (err) {
-		return;
+		return 0;
 	}
 #endif
 
@@ -193,7 +193,7 @@ void main(void)
 	err = lte_lc_init_and_connect();
 	if (err) {
 		printk("Failed to connect to the LTE network, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	printk("OK\n");
@@ -201,7 +201,7 @@ void main(void)
 	err = download_client_init(&downloader, callback);
 	if (err) {
 		printk("Failed to initialize the client, err %d", err);
-		return;
+		return 0;
 	}
 
 #if CONFIG_SAMPLE_COMPUTE_HASH
@@ -212,7 +212,7 @@ void main(void)
 	err = download_client_connect(&downloader, URL, &config);
 	if (err) {
 		printk("Failed to connect, err %d", err);
-		return;
+		return 0;
 	}
 
 	ref_time = k_uptime_get();
@@ -220,8 +220,10 @@ void main(void)
 	err = download_client_start(&downloader, URL, STARTING_OFFSET);
 	if (err) {
 		printk("Failed to start the downloader, err %d", err);
-		return;
+		return 0;
 	}
 
 	printk("Downloading %s\n", URL);
+
+	return 0;
 }
diff --git a/samples/nrf9160/fmfu_smp_svr/src/main.c b/samples/nrf9160/fmfu_smp_svr/src/main.c
index 6a3d80d6175d..e383dc1fb6ed 100644
--- a/samples/nrf9160/fmfu_smp_svr/src/main.c
+++ b/samples/nrf9160/fmfu_smp_svr/src/main.c
@@ -11,7 +11,7 @@
 #include <modem/nrf_modem_lib.h>
 #include <zephyr/dfu/mcuboot.h>
 
-void main(void)
+int main(void)
 {
 	int err = nrf_modem_lib_init();
 
@@ -46,4 +46,6 @@ void main(void)
 	} else {
 		printk("Current image not confirmed yet\n\r");
 	}
+
+	return 0;
 }
diff --git a/samples/nrf9160/http_update/application_update/src/main.c b/samples/nrf9160/http_update/application_update/src/main.c
index 5b1729ea082a..dedb4127856d 100644
--- a/samples/nrf9160/http_update/application_update/src/main.c
+++ b/samples/nrf9160/http_update/application_update/src/main.c
@@ -171,7 +171,7 @@ int lwm2m_carrier_event_handler(const lwm2m_carrier_event_t *event)
 }
 #endif /* CONFIG_LWM2M_CARRIER */
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -182,7 +182,7 @@ void main(void)
 	err = nrf_modem_lib_init();
 	if (err) {
 		printk("Failed to initialize modem library!");
-		return;
+		return 0;
 	}
 #endif
 	/* This is needed so that MCUBoot won't revert the update */
@@ -191,7 +191,7 @@ void main(void)
 	err = fota_download_init(fota_dl_handler);
 	if (err != 0) {
 		printk("fota_download_init() failed, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	err = update_sample_init(&(struct update_sample_init_params){
@@ -201,8 +201,10 @@ void main(void)
 				});
 	if (err != 0) {
 		printk("update_sample_init() failed, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Press Button 1 or enter 'download' to download firmware update\n");
+
+	return 0;
 }
diff --git a/samples/nrf9160/http_update/full_modem_update/src/main.c b/samples/nrf9160/http_update/full_modem_update/src/main.c
index 5b6623a346eb..21955094ce60 100644
--- a/samples/nrf9160/http_update/full_modem_update/src/main.c
+++ b/samples/nrf9160/http_update/full_modem_update/src/main.c
@@ -193,7 +193,7 @@ static int shell_flash(const struct shell *shell, size_t argc, char **argv)
 
 SHELL_CMD_REGISTER(flash, NULL, "For rebooting device", shell_flash);
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -201,7 +201,7 @@ void main(void)
 
 	if (!device_is_ready(flash_dev)) {
 		printk("Flash device %s not ready\n", flash_dev->name);
-		return;
+		return 0;
 	}
 
 	err = nrf_modem_lib_init();
@@ -217,13 +217,13 @@ void main(void)
 	err = button_init();
 	if (err != 0) {
 		printk("button_init() failed: %d\n", err);
-		return;
+		return 0;
 	}
 
 	err = fota_download_init(fota_dl_handler);
 	if (err != 0) {
 		printk("fota_download_init() failed, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	const struct dfu_target_full_modem_params params = {
@@ -237,13 +237,13 @@ void main(void)
 	err = dfu_target_full_modem_cfg(&params);
 	if (err != 0) {
 		printk("dfu_target_full_modem_cfg failed: %d\n", err);
-		return;
+		return 0;
 	}
 
 	err = modem_info_init();
 	if (err != 0) {
 		printk("modem_info_init failed: %d\n", err);
-		return;
+		return 0;
 	}
 
 	modem_info_string_get(MODEM_INFO_FW_VERSION, modem_version,
@@ -257,9 +257,11 @@ void main(void)
 				});
 	if (err != 0) {
 		printk("update_sample_init() failed, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Press Button 1 or enter 'download' to download firmware update\n");
 	printk("Press Button 2 or enter 'flash' to apply modem firmware update from flash\n");
+
+	return 0;
 }
diff --git a/samples/nrf9160/http_update/modem_delta_update/src/main.c b/samples/nrf9160/http_update/modem_delta_update/src/main.c
index 0a26d3332320..6f24467a9e0e 100644
--- a/samples/nrf9160/http_update/modem_delta_update/src/main.c
+++ b/samples/nrf9160/http_update/modem_delta_update/src/main.c
@@ -77,7 +77,7 @@ static int num_leds(void)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -111,7 +111,7 @@ void main(void)
 	case -1:
 		printk("Could not initialize momdem library.\n");
 		printk("Fatal error.\n");
-		return;
+		return 0;
 	default:
 		break;
 	}
@@ -120,7 +120,7 @@ void main(void)
 	err = fota_download_init(fota_dl_handler);
 	if (err != 0) {
 		printk("fota_download_init() failed, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	err = update_sample_init(&(struct update_sample_init_params){
@@ -130,10 +130,12 @@ void main(void)
 				});
 	if (err != 0) {
 		printk("update_sample_init() failed, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Current modem firmware version: %s\n", version);
 
 	printk("Press Button 1 for enter 'download' to download modem delta update\n");
+
+	return 0;
 }
diff --git a/samples/nrf9160/https_client/src/main.c b/samples/nrf9160/https_client/src/main.c
index 534c87feac6d..4fed628cbe34 100644
--- a/samples/nrf9160/https_client/src/main.c
+++ b/samples/nrf9160/https_client/src/main.c
@@ -165,7 +165,7 @@ int tls_setup(int fd)
 	return 0;
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 	int fd;
@@ -184,7 +184,7 @@ void main(void)
 	err = nrf_modem_lib_init();
 	if (err) {
 		printk("Modem library initialization failed, error: %d\n", err);
-		return;
+		return 0;
 	}
 
 	/* Setup a callback for the default PDP context (zero).
@@ -194,14 +194,14 @@ void main(void)
 	err = pdn_default_ctx_cb_reg(pdn_event_handler);
 	if (err) {
 		printk("pdn_default_ctx_cb_reg() failed, err %d\n", err);
-		return;
+		return 0;
 	}
 
 #if !defined(CONFIG_SAMPLE_TFM_MBEDTLS)
 	/* Provision certificates before connecting to the LTE network */
 	err = cert_provision();
 	if (err) {
-		return;
+		return 0;
 	}
 #endif
 
@@ -209,7 +209,7 @@ void main(void)
 	err = lte_lc_init_and_connect();
 	if (err) {
 		printk("Failed to connect to the LTE network, err %d\n", err);
-		return;
+		return 0;
 	}
 	printk("OK\n");
 
@@ -226,7 +226,7 @@ void main(void)
 	err = getaddrinfo(HTTPS_HOSTNAME, HTTPS_PORT, &hints, &res);
 	if (err) {
 		printk("getaddrinfo() failed, err %d\n", errno);
-		return;
+		return 0;
 	}
 
 	inet_ntop(res->ai_family, &((struct sockaddr_in *)(res->ai_addr))->sin_addr, peer_addr,
@@ -303,4 +303,6 @@ void main(void)
 	(void)close(fd);
 
 	lte_lc_power_off();
+
+	return 0;
 }
diff --git a/samples/nrf9160/lte_ble_gateway/src/main.c b/samples/nrf9160/lte_ble_gateway/src/main.c
index 9cb26d337299..e6b6a1303087 100644
--- a/samples/nrf9160/lte_ble_gateway/src/main.c
+++ b/samples/nrf9160/lte_ble_gateway/src/main.c
@@ -573,7 +573,7 @@ static void buttons_leds_init(void)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	LOG_INF("LTE Sensor Gateway sample started");
 
@@ -584,4 +584,6 @@ void main(void)
 	modem_configure();
 	cloud_init();
 	cloud_connect(NULL);
+
+	return 0;
 }
diff --git a/samples/nrf9160/lwm2m_carrier/src/main.c b/samples/nrf9160/lwm2m_carrier/src/main.c
index 472fc8101a57..2c7b18504938 100644
--- a/samples/nrf9160/lwm2m_carrier/src/main.c
+++ b/samples/nrf9160/lwm2m_carrier/src/main.c
@@ -159,7 +159,8 @@ int lwm2m_carrier_event_handler(const lwm2m_carrier_event_t *event)
 }
 #endif /* CONFIG_LWM2M_CARRIER */
 
-void main(void)
+int main(void)
 {
 	printk("LWM2M Carrier library sample.\n");
+	return 0;
 }
diff --git a/samples/nrf9160/lwm2m_client/src/ipso/ipso_colour_sensor.c b/samples/nrf9160/lwm2m_client/src/ipso/ipso_colour_sensor.c
index c0b261184049..13f41caf0685 100644
--- a/samples/nrf9160/lwm2m_client/src/ipso/ipso_colour_sensor.c
+++ b/samples/nrf9160/lwm2m_client/src/ipso/ipso_colour_sensor.c
@@ -112,7 +112,7 @@ static struct lwm2m_engine_obj_inst *colour_sensor_create(uint16_t obj_inst_id)
 	return &inst[index];
 }
 
-static int ipso_colour_sensor_init(const struct device *dev)
+static int ipso_colour_sensor_init(void)
 {
 	sensor.obj_id = IPSO_OBJECT_COLOUR_ID;
 	sensor.version_major = COLOUR_VERSION_MAJOR;
diff --git a/samples/nrf9160/lwm2m_client/src/main.c b/samples/nrf9160/lwm2m_client/src/main.c
index e7cd7ee4184b..4d0928dc52e1 100644
--- a/samples/nrf9160/lwm2m_client/src/main.c
+++ b/samples/nrf9160/lwm2m_client/src/main.c
@@ -184,7 +184,7 @@ void send_periodically_work_handler(struct k_work *work)
 	};
 
 	/* lwm2m send post to server */
-	ret = lwm2m_send(&client, send_path, 4, true);
+	ret = lwm2m_send_cb(&client, send_path, 4, NULL);
 	if (ret) {
 		if (ret == EPERM) {
 			LOG_INF("Server Mute send block send operation");
@@ -580,7 +580,7 @@ static void suspend_lwm2m_engine(void)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int ret;
 	uint32_t bootstrap_flags = 0;
@@ -590,20 +590,20 @@ void main(void)
 	ret = nrf_modem_lib_init();
 	if (ret < 0) {
 		LOG_ERR("Unable to init modem library (%d)", ret);
-		return;
+		return 0;
 	}
 
 	ret = app_event_manager_init();
 	if (ret) {
 		LOG_ERR("Unable to init Application Event Manager (%d)", ret);
-		return;
+		return 0;
 	}
 
 	LOG_INF("Initializing modem.");
 	ret = lte_lc_init();
 	if (ret < 0) {
 		LOG_ERR("Unable to init modem (%d)", ret);
-		return;
+		return 0;
 	}
 
 	lte_lc_register_handler(lte_notify_handler);
@@ -611,14 +611,14 @@ void main(void)
 	ret = modem_info_init();
 	if (ret < 0) {
 		LOG_ERR("Unable to init modem_info (%d)", ret);
-		return;
+		return 0;
 	}
 
 	/* query IMEI */
 	ret = modem_info_string_get(MODEM_INFO_IMEI, imei_buf, sizeof(imei_buf));
 	if (ret < 0) {
 		LOG_ERR("Unable to get IMEI");
-		return;
+		return 0;
 	}
 
 	/* use IMEI as unique endpoint name */
@@ -630,14 +630,14 @@ void main(void)
 	ret = lwm2m_setup();
 	if (ret < 0) {
 		LOG_ERR("Failed to setup LWM2M fields (%d)", ret);
-		return;
+		return 0;
 	}
 
 #if defined(CONFIG_LWM2M_CLIENT_UTILS_FIRMWARE_UPDATE_OBJ_SUPPORT)
 	ret = lwm2m_init_image();
 	if (ret < 0) {
 		LOG_ERR("Failed to setup image properties (%d)", ret);
-		return;
+		return 0;
 	}
 #endif
 
@@ -771,4 +771,6 @@ void main(void)
 		/* Wait for statmachine update event */
 		k_sem_take(&state_mutex, K_FOREVER);
 	}
+
+	return 0;
 }
diff --git a/samples/nrf9160/memfault/src/main.c b/samples/nrf9160/memfault/src/main.c
index f34fdc2f11f3..f959da7b79b4 100644
--- a/samples/nrf9160/memfault/src/main.c
+++ b/samples/nrf9160/memfault/src/main.c
@@ -181,7 +181,7 @@ static void handle_lte_connection_started(void)
 	memfault_zephyr_port_post_data();
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
diff --git a/samples/nrf9160/modem_callbacks/src/main.c b/samples/nrf9160/modem_callbacks/src/main.c
index 7ed5fef35c8a..50ccad30ee8a 100644
--- a/samples/nrf9160/modem_callbacks/src/main.c
+++ b/samples/nrf9160/modem_callbacks/src/main.c
@@ -30,7 +30,7 @@ static void on_cfun(enum lte_lc_func_mode mode, void *ctx)
 	printk("> Functional mode has changed to %d\n", mode);
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -40,7 +40,7 @@ void main(void)
 	err = nrf_modem_lib_init();
 	if (err) {
 		printk("Modem initialization failed, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Changing functional mode\n");
@@ -53,8 +53,10 @@ void main(void)
 	err = nrf_modem_lib_shutdown();
 	if (err) {
 		printk("Shutting down modem failed, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Bye\n");
+
+	return 0;
 }
diff --git a/samples/nrf9160/modem_shell/src/cloud/cloud_lwm2m.c b/samples/nrf9160/modem_shell/src/cloud/cloud_lwm2m.c
index 26f90e1419c1..8d50099c0f20 100644
--- a/samples/nrf9160/modem_shell/src/cloud/cloud_lwm2m.c
+++ b/samples/nrf9160/modem_shell/src/cloud/cloud_lwm2m.c
@@ -154,7 +154,7 @@ static void cloud_lwm2m_lte_lc_evt_handler(const struct lte_lc_evt *const evt)
 	}
 }
 
-static int cloud_lwm2m_init(const struct device *unused)
+static int cloud_lwm2m_init(void)
 {
 	int ret;
 
diff --git a/samples/nrf9160/modem_shell/src/main.c b/samples/nrf9160/modem_shell/src/main.c
index 6de05369878f..f2fee72d6ce2 100644
--- a/samples/nrf9160/modem_shell/src/main.c
+++ b/samples/nrf9160/modem_shell/src/main.c
@@ -198,7 +198,7 @@ static void button_handler(uint32_t button_states, uint32_t has_changed)
 }
 #endif
 
-void main(void)
+int main(void)
 {
 	int err;
 	struct k_work_queue_config cfg = {
@@ -255,19 +255,19 @@ void main(void)
 		printk("Modem firmware update successful!\n");
 		printk("Modem will run the new firmware after reboot\n");
 		sys_reboot(SYS_REBOOT_WARM);
-		return;
+		return 0;
 	case NRF_MODEM_DFU_RESULT_UUID_ERROR:
 	case NRF_MODEM_DFU_RESULT_AUTH_ERROR:
 		printk("Modem firmware update failed!\n");
 		printk("Modem will run non-updated firmware on reboot.\n");
 		sys_reboot(SYS_REBOOT_WARM);
-		return;
+		return 0;
 	case NRF_MODEM_DFU_RESULT_HARDWARE_ERROR:
 	case NRF_MODEM_DFU_RESULT_INTERNAL_ERROR:
 		printk("Modem firmware update failed!\n");
 		printk("Fatal error.\n");
 		sys_reboot(SYS_REBOOT_WARM);
-		return;
+		return 0;
 	case NRF_MODEM_DFU_RESULT_VOLTAGE_LOW:
 		printk("Modem firmware update cancelled due to low power.\n");
 		printk("Please reboot once you have sufficient power for the DFU\n");
@@ -276,7 +276,7 @@ void main(void)
 		/* Modem library initialization failed. */
 		printk("Could not initialize nrf_modem_lib, err %d.\n", err);
 		printk("Fatal error.\n");
-		return;
+		return 0;
 	}
 #else
 	/* Wait until the LwM2M carrier library has initialized the modem library. */
@@ -308,7 +308,7 @@ void main(void)
 	err = modem_info_init();
 	if (err) {
 		printk("Modem info could not be established: %d\n", err);
-		return;
+		return 0;
 	}
 #endif
 
@@ -346,4 +346,6 @@ void main(void)
 		at_cmd_mode_start(mosh_shell);
 	}
 #endif
+
+	return 0;
 }
diff --git a/samples/nrf9160/modem_trace_backend/src/main.c b/samples/nrf9160/modem_trace_backend/src/main.c
index cf57b8bc0c77..7fde3abe6714 100644
--- a/samples/nrf9160/modem_trace_backend/src/main.c
+++ b/samples/nrf9160/modem_trace_backend/src/main.c
@@ -18,7 +18,7 @@ static void on_cfun(enum lte_lc_func_mode mode, void *context)
 	printk("LTE mode changed to %d\n", mode);
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -28,14 +28,14 @@ void main(void)
 	err = nrf_modem_lib_init();
 	if (err) {
 		printk("Modem library initialization failed, error: %d\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Connecting to network\n");
 	err = lte_lc_func_mode_set(LTE_LC_FUNC_MODE_NORMAL);
 	if (err) {
 		printk("Failed to change LTE mode, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	k_sleep(K_SECONDS(5));
@@ -43,10 +43,12 @@ void main(void)
 	err = lte_lc_func_mode_set(LTE_LC_FUNC_MODE_POWER_OFF);
 	if (err) {
 		printk("Failed to change LTE mode, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	nrf_modem_lib_shutdown();
 
 	printk("Bye\n");
+
+	return 0;
 }
diff --git a/samples/nrf9160/modem_trace_flash/src/main.c b/samples/nrf9160/modem_trace_flash/src/main.c
index d90e3d3cb131..a17e58915d9a 100644
--- a/samples/nrf9160/modem_trace_flash/src/main.c
+++ b/samples/nrf9160/modem_trace_flash/src/main.c
@@ -99,7 +99,7 @@ void nrf_modem_lib_trace_callback(enum nrf_modem_lib_trace_event evt)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -126,7 +126,7 @@ void main(void)
 	err = lte_lc_func_mode_set(LTE_LC_FUNC_MODE_NORMAL);
 	if (err) {
 		LOG_ERR("Failed to change LTE mode, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	/* Leave the modem on for 10 seconds */
@@ -135,7 +135,7 @@ void main(void)
 	err = lte_lc_func_mode_set(LTE_LC_FUNC_MODE_POWER_OFF);
 	if (err) {
 		LOG_ERR("Failed to change LTE mode, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	/* Give the modem some time to turn off and receive traces */
@@ -155,4 +155,6 @@ void main(void)
 
 	LOG_INF("Press button 1 to print traces to UART");
 	LOG_INF("Press button 2 to restart application (warm boot)");
+
+	return 0;
 }
diff --git a/samples/nrf9160/nidd/src/main.c b/samples/nrf9160/nidd/src/main.c
index 22d1a2d1b873..d017a8150740 100644
--- a/samples/nrf9160/nidd/src/main.c
+++ b/samples/nrf9160/nidd/src/main.c
@@ -211,7 +211,7 @@ static void nidd_send_and_recv(int fd)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int cid, pdn_id, fd;
 
@@ -242,4 +242,6 @@ void main(void)
 power_off:
 	modem_power_off();
 	printk("NIDD sample done\n");
+
+	return 0;
 }
diff --git a/samples/nrf9160/nrf_cloud_mqtt_multi_service/src/main.c b/samples/nrf9160/nrf_cloud_mqtt_multi_service/src/main.c
index f801295e7094..074280e0cc61 100644
--- a/samples/nrf9160/nrf_cloud_mqtt_multi_service/src/main.c
+++ b/samples/nrf9160/nrf_cloud_mqtt_multi_service/src/main.c
@@ -43,7 +43,8 @@ K_THREAD_DEFINE(con_thread, CONFIG_CONNECTION_THREAD_STACK_SIZE, connection_mana
  * but for illustrative purposes we don't use it. main_application() could be called directly
  * from this function, rather than given its own dedicated thread.
  */
-void main(void)
+int main(void)
 {
 	LOG_INF("nRF Cloud MQTT multi-service sample has started.");
+	return 0;
 }
diff --git a/samples/nrf9160/nrf_cloud_rest_cell_location/src/main.c b/samples/nrf9160/nrf_cloud_rest_cell_location/src/main.c
index 2f0269269fdf..d8458889b6b1 100644
--- a/samples/nrf9160/nrf_cloud_rest_cell_location/src/main.c
+++ b/samples/nrf9160/nrf_cloud_rest_cell_location/src/main.c
@@ -586,7 +586,7 @@ static void connect_to_network(void)
 	modem_time_wait();
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -595,7 +595,7 @@ void main(void)
 	err = init();
 	if (err) {
 		LOG_ERR("Initialization failed");
-		return;
+		return 0;
 	}
 
 	connect_to_network();
diff --git a/samples/nrf9160/nrf_cloud_rest_device_message/src/main.c b/samples/nrf9160/nrf_cloud_rest_device_message/src/main.c
index 834bdaab7082..933827c9be38 100644
--- a/samples/nrf9160/nrf_cloud_rest_device_message/src/main.c
+++ b/samples/nrf9160/nrf_cloud_rest_device_message/src/main.c
@@ -369,7 +369,7 @@ int send_hello_world_msg(void)
 	return err;
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -379,7 +379,7 @@ void main(void)
 	err = setup();
 	if (err) {
 		LOG_ERR("Setup failed, stopping.");
-		return;
+		return 0;
 	}
 
 	rest_ctx.keep_alive = true;
@@ -390,7 +390,7 @@ void main(void)
 	err = send_hello_world_msg();
 	if (err) {
 		LOG_ERR("Hello World failed, stopping.");
-		return;
+		return 0;
 	}
 
 	while (1) {
diff --git a/samples/nrf9160/nrf_cloud_rest_fota/src/main.c b/samples/nrf9160/nrf_cloud_rest_fota/src/main.c
index 706edbffb3cc..ecd428a35282 100644
--- a/samples/nrf9160/nrf_cloud_rest_fota/src/main.c
+++ b/samples/nrf9160/nrf_cloud_rest_fota/src/main.c
@@ -727,7 +727,7 @@ static void error_reboot(void)
 	sys_reboot(SYS_REBOOT_COLD);
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -737,12 +737,12 @@ void main(void)
 	err = init();
 	if (err) {
 		LOG_ERR("Initialization failed");
-		return;
+		return 0;
 	}
 
 	err = connect_to_network();
 	if (err) {
-		return;
+		return 0;
 	}
 
 	/* Now that the device is connected to the network, get the modem info */
diff --git a/samples/nrf9160/pdn/src/main.c b/samples/nrf9160/pdn/src/main.c
index f54fac21b16b..0b4de396a060 100644
--- a/samples/nrf9160/pdn/src/main.c
+++ b/samples/nrf9160/pdn/src/main.c
@@ -92,7 +92,7 @@ void pdn_event_handler(uint8_t cid, enum pdn_event event, int reason)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 	int esm;
@@ -104,7 +104,7 @@ void main(void)
 	err = nrf_modem_lib_init();
 	if (err) {
 		printk("Modem library initialization failed, error: %d\n", err);
-		return;
+		return 0;
 	}
 
 	/* Setup a callback for the default PDP context (zero).
@@ -114,18 +114,18 @@ void main(void)
 	err = pdn_default_ctx_cb_reg(pdn_event_handler);
 	if (err) {
 		printk("pdn_default_ctx_cb_reg() failed, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	err = lte_lc_init_and_connect();
 	if (err) {
-		return;
+		return 0;
 	}
 
 	err = pdn_default_apn_get(apn, sizeof(apn));
 	if (err) {
 		printk("pdn_default_apn_get() failed, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Default APN is %s\n", apn);
@@ -134,7 +134,7 @@ void main(void)
 	err = pdn_ctx_create(&cid, pdn_event_handler);
 	if (err) {
 		printk("pdn_ctx_create() failed, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	printk("Created new PDP context %d\n", cid);
@@ -143,7 +143,7 @@ void main(void)
 	err = pdn_ctx_configure(cid, apn, PDN_FAM_IPV4V6, NULL);
 	if (err) {
 		printk("pdn_ctx_configure() failed, err %d\n", err);
-		return;
+		return 0;
 	}
 
 	printk("PDP context %d configured: APN %s, Family %s\n",
@@ -154,7 +154,7 @@ void main(void)
 	if (err) {
 		printk("pdn_activate() failed, err %d esm %d %s\n",
 			err, esm, pdn_esm_strerror(err));
-		return;
+		return 0;
 	}
 
 	printk("PDP Context %d, PDN ID %d\n", 0, pdn_id_get(0));
@@ -164,4 +164,6 @@ void main(void)
 
 	lte_lc_power_off();
 	printk("Bye\n");
+
+	return 0;
 }
diff --git a/samples/nrf9160/slm_shell/src/main.c b/samples/nrf9160/slm_shell/src/main.c
index ddbfb6580b59..ddeb6684dbe8 100644
--- a/samples/nrf9160/slm_shell/src/main.c
+++ b/samples/nrf9160/slm_shell/src/main.c
@@ -21,9 +21,10 @@ static void cereg_mon(const char *notif)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	LOG_INF("SLM Shell starts on %s", CONFIG_BOARD);
 
 	(void)modem_slm_init(NULL);
+	return 0;
 }
diff --git a/samples/nrf9160/sms/src/main.c b/samples/nrf9160/sms/src/main.c
index f96c3104f481..89054b6a157b 100644
--- a/samples/nrf9160/sms/src/main.c
+++ b/samples/nrf9160/sms/src/main.c
@@ -53,7 +53,7 @@ static void sms_callback(struct sms_data *const data, void *context)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int handle = 0;
 	int ret = 0;
@@ -63,19 +63,19 @@ void main(void)
 	ret = nrf_modem_lib_init();
 	if (ret) {
 		printk("Modem library initialization failed, error: %d\n", ret);
-		return;
+		return 0;
 	}
 
 	ret = lte_lc_init_and_connect();
 	if (ret) {
 		printk("Lte_lc failed to initialize and connect, err %d", ret);
-		return;
+		return 0;
 	}
 
 	handle = sms_register_listener(sms_callback, NULL);
 	if (handle) {
 		printk("sms_register_listener returned err: %d\n", handle);
-		return;
+		return 0;
 	}
 
 	printk("SMS sample is ready for receiving messages\n");
@@ -100,4 +100,5 @@ void main(void)
 	 * However, this sample will continue to be registered for
 	 * received SMS messages and they can be seen in serial port log.
 	 */
+	return 0;
 }
diff --git a/samples/nrf9160/udp/src/main.c b/samples/nrf9160/udp/src/main.c
index eb1986b5d7f2..464c55f8fe89 100644
--- a/samples/nrf9160/udp/src/main.c
+++ b/samples/nrf9160/udp/src/main.c
@@ -208,7 +208,7 @@ static int server_connect(void)
 	return err;
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -238,14 +238,16 @@ void main(void)
 	err = server_init();
 	if (err) {
 		printk("Not able to initialize UDP server connection\n");
-		return;
+		return 0;
 	}
 
 	err = server_connect();
 	if (err) {
 		printk("Not able to connect to UDP server\n");
-		return;
+		return 0;
 	}
 
 	k_work_schedule(&server_transmission_work, K_NO_WAIT);
+
+	return 0;
 }
diff --git a/samples/nrf_profiler/src/main.c b/samples/nrf_profiler/src/main.c
index ff441061e9cb..d3e3e26755e3 100644
--- a/samples/nrf_profiler/src/main.c
+++ b/samples/nrf_profiler/src/main.c
@@ -55,7 +55,7 @@ static void register_nrf_profiler_events(void)
 						     data_types, 5);
 }
 
-void main(void)
+int main(void)
 {
 	if (nrf_profiler_init()) {
 		printk("Profiler failed to initialize\n");
@@ -89,7 +89,7 @@ void main(void)
 
 		if ((err < 0) || (err >= sizeof(string))) {
 			printk("snprintf error: %d\n", err);
-			return;
+			return 0;
 		}
 
 		profile_no_data_event();
diff --git a/samples/nrf_rpc/entropy_nrf53/cpuapp/src/entropy_ser.c b/samples/nrf_rpc/entropy_nrf53/cpuapp/src/entropy_ser.c
index 0b657a1386eb..3011a438d0f8 100644
--- a/samples/nrf_rpc/entropy_nrf53/cpuapp/src/entropy_ser.c
+++ b/samples/nrf_rpc/entropy_nrf53/cpuapp/src/entropy_ser.c
@@ -273,9 +273,8 @@ static void err_handler(const struct nrf_rpc_err_report *report)
 }
 
 
-static int serialization_init(const struct device *dev)
+static int serialization_init(void)
 {
-	ARG_UNUSED(dev);
 
 	int err;
 
diff --git a/samples/nrf_rpc/entropy_nrf53/cpuapp/src/main.c b/samples/nrf_rpc/entropy_nrf53/cpuapp/src/main.c
index 71aaa1d8f8e8..d464d7c69906 100644
--- a/samples/nrf_rpc/entropy_nrf53/cpuapp/src/main.c
+++ b/samples/nrf_rpc/entropy_nrf53/cpuapp/src/main.c
@@ -30,7 +30,7 @@ static void result_callback(int result, uint8_t *buffer, size_t length)
 	printk("\n");
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
@@ -39,7 +39,7 @@ void main(void)
 	err = entropy_remote_init();
 	if (err) {
 		printk("Remote entropy driver initialization failed\n");
-		return;
+		return 0;
 	}
 
 	printk("Remote init send\n");
diff --git a/samples/nrf_rpc/entropy_nrf53/cpunet/src/entropy_ser.c b/samples/nrf_rpc/entropy_nrf53/cpunet/src/entropy_ser.c
index d345aa450572..b6ee9e7e06c5 100644
--- a/samples/nrf_rpc/entropy_nrf53/cpunet/src/entropy_ser.c
+++ b/samples/nrf_rpc/entropy_nrf53/cpunet/src/entropy_ser.c
@@ -173,9 +173,8 @@ static void err_handler(const struct nrf_rpc_err_report *report)
 }
 
 
-static int serialization_init(const struct device *dev)
+static int serialization_init(void)
 {
-	ARG_UNUSED(dev);
 
 	int err;
 
diff --git a/samples/nrf_rpc/entropy_nrf53/cpunet/src/main.c b/samples/nrf_rpc/entropy_nrf53/cpunet/src/main.c
index b7399229e25e..0df4dc664327 100644
--- a/samples/nrf_rpc/entropy_nrf53/cpunet/src/main.c
+++ b/samples/nrf_rpc/entropy_nrf53/cpunet/src/main.c
@@ -6,7 +6,7 @@
 
 #include <zephyr/kernel.h>
 
-void main(void)
+int main(void)
 {
 	/* The only activity of this application is interaction with the APP
 	 * core using serialized communication through the nRF RPC library.
@@ -14,4 +14,5 @@ void main(void)
 	 * and start at system boot.
 	 */
 	printk("Entropy sample started[NET Core].\n");
+	return 0;
 }
diff --git a/samples/openthread/cli/src/main.c b/samples/openthread/cli/src/main.c
index 899b731f0e06..c74cc9179ae8 100644
--- a/samples/openthread/cli/src/main.c
+++ b/samples/openthread/cli/src/main.c
@@ -30,7 +30,7 @@ LOG_MODULE_REGISTER(cli_sample, CONFIG_OT_COMMAND_LINE_INTERFACE_LOG_LEVEL);
 	"documentation at:\n\r" \
 	"https://github.com/openthread/openthread/blob/master/src/cli/README.md\n\r"
 
-void main(void)
+int main(void)
 {
 #if DT_NODE_HAS_COMPAT(DT_CHOSEN(zephyr_shell_uart), zephyr_cdc_acm_uart)
 	int ret;
@@ -40,13 +40,13 @@ void main(void)
 	ret = usb_enable(NULL);
 	if (ret != 0) {
 		LOG_ERR("Failed to enable USB");
-		return;
+		return 0;
 	}
 
 	dev = DEVICE_DT_GET(DT_CHOSEN(zephyr_shell_uart));
 	if (dev == NULL) {
 		LOG_ERR("Failed to find specific UART device");
-		return;
+		return 0;
 	}
 
 	LOG_INF("Waiting for host to be ready to communicate");
@@ -77,4 +77,6 @@ void main(void)
 #if defined(CONFIG_CLI_SAMPLE_LOW_POWER)
 	low_power_enable();
 #endif
+
+	return 0;
 }
diff --git a/samples/openthread/coap_client/src/coap_client.c b/samples/openthread/coap_client/src/coap_client.c
index 6e4ac89485e2..3eea8ec6a0e1 100644
--- a/samples/openthread/coap_client/src/coap_client.c
+++ b/samples/openthread/coap_client/src/coap_client.c
@@ -120,7 +120,7 @@ static void on_button_changed(uint32_t button_state, uint32_t has_changed)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int ret;
 
@@ -133,13 +133,13 @@ void main(void)
 	ret = dk_buttons_init(on_button_changed);
 	if (ret) {
 		LOG_ERR("Cannot init buttons (error: %d)", ret);
-		return;
+		return 0;
 	}
 
 	ret = dk_leds_init();
 	if (ret) {
 		LOG_ERR("Cannot init leds, (error: %d)", ret);
-		return;
+		return 0;
 	}
 
 #if CONFIG_BT_NUS
@@ -151,10 +151,12 @@ void main(void)
 	ret = ble_utils_init(&nus_clbs, on_ble_connect, on_ble_disconnect);
 	if (ret) {
 		LOG_ERR("Cannot init BLE utilities");
-		return;
+		return 0;
 	}
 
 #endif /* CONFIG_BT_NUS */
 
 	coap_client_utils_init(on_ot_connect, on_ot_disconnect, on_mtd_mode_toggle);
+
+	return 0;
 }
diff --git a/samples/openthread/coap_server/src/coap_server.c b/samples/openthread/coap_server/src/coap_server.c
index 9c6ce63605af..6327a3ab77fa 100644
--- a/samples/openthread/coap_server/src/coap_server.c
+++ b/samples/openthread/coap_server/src/coap_server.c
@@ -127,7 +127,7 @@ static void on_thread_state_changed(otChangedFlags flags, struct openthread_cont
 static struct openthread_state_changed_cb ot_state_chaged_cb = { .state_changed_cb =
 									 on_thread_state_changed };
 
-void main(void)
+int main(void)
 {
 	int ret;
 
@@ -160,5 +160,5 @@ void main(void)
 	openthread_start(openthread_get_default_context());
 
 end:
-	return;
+	return 0;
 }
diff --git a/samples/openthread/coprocessor/src/main.c b/samples/openthread/coprocessor/src/main.c
index a9436f1bcfca..6cab1a247df6 100644
--- a/samples/openthread/coprocessor/src/main.c
+++ b/samples/openthread/coprocessor/src/main.c
@@ -15,7 +15,8 @@ LOG_MODULE_REGISTER(coprocessor_sample, CONFIG_OT_COPROCESSOR_LOG_LEVEL);
 	"OpenThread Coprocessor application is now running on NCS.\n\r"        \
 	"=========================================================\n\r"
 
-void main(void)
+int main(void)
 {
 	LOG_INF(WELCOME_TEXT);
+	return 0;
 }
diff --git a/samples/peripheral/802154_phy_test/src/main.c b/samples/peripheral/802154_phy_test/src/main.c
index d1c2eac470df..292e0a1253ca 100644
--- a/samples/peripheral/802154_phy_test/src/main.c
+++ b/samples/peripheral/802154_phy_test/src/main.c
@@ -27,22 +27,20 @@ void ptt_do_reset_ext(void)
 	NVIC_SystemReset();
 }
 
-static int rf_setup(const struct device *dev)
+static int rf_setup(void)
 {
 	LOG_INF("RF setup started");
 
-	ARG_UNUSED(dev);
 
 	rf_init();
 
 	return 0;
 }
 
-static int setup(const struct device *dev)
+static int setup(void)
 {
 	LOG_INF("Setup started");
 
-	ARG_UNUSED(dev);
 
 	periph_init();
 
diff --git a/samples/peripheral/lpuart/boards/nrf21540dk_nrf52840.overlay b/samples/peripheral/lpuart/boards/nrf21540dk_nrf52840.overlay
index 49698afc8a84..e7f2d1fb7b8f 100644
--- a/samples/peripheral/lpuart/boards/nrf21540dk_nrf52840.overlay
+++ b/samples/peripheral/lpuart/boards/nrf21540dk_nrf52840.overlay
@@ -37,3 +37,7 @@
 		};
 	};
 };
+
+&rtc2 {
+	status = "okay";
+};
diff --git a/samples/peripheral/lpuart/boards/nrf52833dk_nrf52833.overlay b/samples/peripheral/lpuart/boards/nrf52833dk_nrf52833.overlay
index dc510cf2c5eb..b9b36fe0a67b 100644
--- a/samples/peripheral/lpuart/boards/nrf52833dk_nrf52833.overlay
+++ b/samples/peripheral/lpuart/boards/nrf52833dk_nrf52833.overlay
@@ -37,3 +37,7 @@
 		};
 	};
 };
+
+&rtc2 {
+	status = "okay";
+};
diff --git a/samples/peripheral/lpuart/boards/nrf52840dk_nrf52840.overlay b/samples/peripheral/lpuart/boards/nrf52840dk_nrf52840.overlay
index df799d163f6d..b4200293ce94 100644
--- a/samples/peripheral/lpuart/boards/nrf52840dk_nrf52840.overlay
+++ b/samples/peripheral/lpuart/boards/nrf52840dk_nrf52840.overlay
@@ -37,3 +37,7 @@
 		};
 	};
 };
+
+&rtc2 {
+	status = "okay";
+};
diff --git a/samples/peripheral/lpuart/boards/nrf52dk_nrf52832.overlay b/samples/peripheral/lpuart/boards/nrf52dk_nrf52832.overlay
index 9a2dbdef38b9..4d1aabdf5ebb 100644
--- a/samples/peripheral/lpuart/boards/nrf52dk_nrf52832.overlay
+++ b/samples/peripheral/lpuart/boards/nrf52dk_nrf52832.overlay
@@ -35,3 +35,7 @@
 	};
 
 };
+
+&rtc2 {
+	status = "okay";
+};
diff --git a/samples/peripheral/lpuart/boards/nrf5340dk_nrf5340_cpuapp.overlay b/samples/peripheral/lpuart/boards/nrf5340dk_nrf5340_cpuapp.overlay
index a24596038df5..b8d1e2faf309 100644
--- a/samples/peripheral/lpuart/boards/nrf5340dk_nrf5340_cpuapp.overlay
+++ b/samples/peripheral/lpuart/boards/nrf5340dk_nrf5340_cpuapp.overlay
@@ -55,3 +55,7 @@
 		};
 	};
 };
+
+&rtc0 {
+	status = "okay";
+};
diff --git a/samples/peripheral/lpuart/boards/nrf9160dk_nrf9160_ns.overlay b/samples/peripheral/lpuart/boards/nrf9160dk_nrf9160_ns.overlay
index 12b9722d1bc6..62a79415985c 100644
--- a/samples/peripheral/lpuart/boards/nrf9160dk_nrf9160_ns.overlay
+++ b/samples/peripheral/lpuart/boards/nrf9160dk_nrf9160_ns.overlay
@@ -38,3 +38,7 @@
 		};
 	};
 };
+
+&rtc0 {
+	status = "okay";
+};
diff --git a/samples/peripheral/lpuart/src/main.c b/samples/peripheral/lpuart/src/main.c
index aa10c3a14af7..0a0a9a9571de 100644
--- a/samples/peripheral/lpuart/src/main.c
+++ b/samples/peripheral/lpuart/src/main.c
@@ -119,7 +119,7 @@ static void async(const struct device *lpuart)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	const struct device *lpuart = DEVICE_DT_GET(DT_NODELABEL(lpuart));
 
@@ -130,4 +130,6 @@ void main(void)
 	} else {
 		async(lpuart);
 	}
+
+	return 0;
 }
diff --git a/samples/peripheral/radio_test/src/main.c b/samples/peripheral/radio_test/src/main.c
index ed81fe8710d9..3bc26f7cc7b8 100644
--- a/samples/peripheral/radio_test/src/main.c
+++ b/samples/peripheral/radio_test/src/main.c
@@ -40,9 +40,11 @@ static void clock_init(void)
 	printk("Clock has started\n");
 }
 
-void main(void)
+int main(void)
 {
 	printk("Starting Radio Test example\n");
 
 	clock_init();
+
+	return 0;
 }
diff --git a/samples/peripheral/radio_test/src/radio_cmd.c b/samples/peripheral/radio_test/src/radio_cmd.c
index cfa67a7b189b..fe9dc78d3647 100644
--- a/samples/peripheral/radio_test/src/radio_cmd.c
+++ b/samples/peripheral/radio_test/src/radio_cmd.c
@@ -1364,9 +1364,8 @@ SHELL_CMD_REGISTER(fem,
 		   cmd_fem);
 #endif /* CONFIG_FEM */
 
-static int radio_cmd_init(const struct device *dev)
+static int radio_cmd_init(void)
 {
-	ARG_UNUSED(dev);
 
 #if CONFIG_RADIO_TEST_POWER_CONTROL_AUTOMATIC
 	/* When front-end module is used, set output power to the front-end module
diff --git a/samples/sensor/bh1749/src/main.c b/samples/sensor/bh1749/src/main.c
index e1c09cb65489..48cad8721764 100644
--- a/samples/sensor/bh1749/src/main.c
+++ b/samples/sensor/bh1749/src/main.c
@@ -130,7 +130,7 @@ static void process(const struct device *dev)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	const struct device *dev = DEVICE_DT_GET_ONE(rohm_bh1749);
 
@@ -141,9 +141,11 @@ void main(void)
 
 	if (!device_is_ready(dev)) {
 		printk("Sensor device not ready\n");
-		return;
+		return 0;
 	}
 
 	printk("device is %p, name is %s\n", dev, dev->name);
 	process(dev);
+
+	return 0;
 }
diff --git a/samples/tfm/provisioning_image/src/main.c b/samples/tfm/provisioning_image/src/main.c
index adc8330f0b26..4d99a90b54e2 100644
--- a/samples/tfm/provisioning_image/src/main.c
+++ b/samples/tfm/provisioning_image/src/main.c
@@ -25,7 +25,7 @@ void provision_implementation_id(void)
 		num_words_to_write);
 }
 
-void main(void)
+int main(void)
 {
 	enum lcs lcs;
 	int err;
@@ -33,12 +33,12 @@ void main(void)
 	err = read_life_cycle_state(&lcs);
 	if (err != 0) {
 		LOG_INF("Failure: Cannot read PSA lifecycle state. Exiting!");
-		return;
+		return 0;
 	}
 
 	if (lcs != BL_STORAGE_LCS_ASSEMBLY) {
 		LOG_INF("Failure: Lifecycle state is not ASSEMBLY as expected. Exiting!");
-		return;
+		return 0;
 	}
 
 	LOG_INF("Successfully verified PSA lifecycle state ASSEMBLY!");
@@ -46,19 +46,19 @@ void main(void)
 	err = update_life_cycle_state(BL_STORAGE_LCS_PROVISIONING);
 	if (err != 0) {
 		LOG_INF("Failure: Cannot set PSA lifecycle state PROVISIONING. Exiting!");
-		return;
+		return 0;
 	}
 
 	err = read_life_cycle_state(&lcs);
 	if (err != 0) {
 		LOG_INF("Failure: Cannot read PSA lifecycle state. Exiting!");
-		return;
+		return 0;
 	}
 
 	if (lcs != BL_STORAGE_LCS_PROVISIONING) {
 		LOG_INF("Lifecycle state was %d", lcs);
 		LOG_INF("Failure: Lifecycle state is not PROVISION as expected. Exiting!");
-		return;
+		return 0;
 	}
 
 	LOG_INF("Successfully switched to PSA lifecycle state PROVISIONING!");
@@ -68,7 +68,7 @@ void main(void)
 
 	if (identity_key_is_written()) {
 		LOG_INF("Failure: Identity key slot already written. Exiting!");
-		return;
+		return 0;
 	}
 
 	LOG_INF("Writing the identity key to KMU");
@@ -81,10 +81,12 @@ void main(void)
 
 	if (!identity_key_is_written()) {
 		LOG_INF("Failure: Identity key is not written! Exiting!");
-		return;
+		return 0;
 	}
 
 	provision_implementation_id();
 
 	LOG_INF("Success!");
+
+	return 0;
 }
diff --git a/samples/tfm/provisioning_image_net_core/src/main.c b/samples/tfm/provisioning_image_net_core/src/main.c
index cd7bd88b2adf..a03092cc2a6c 100644
--- a/samples/tfm/provisioning_image_net_core/src/main.c
+++ b/samples/tfm/provisioning_image_net_core/src/main.c
@@ -8,18 +8,20 @@
 #include <stdio.h>
 #include <nrfx_nvmc.h>
 
-void main(void)
+int main(void)
 {
 	bool is_writable = nrfx_nvmc_word_writable_check((uint32_t)&NRF_UICR->APPROTECT,
 		UICR_APPROTECT_PALL_Protected);
 
 	if (!is_writable) {
 		printk("Cannot write to the UICR->APPROTECT register, exiting...!\n");
-		return;
+		return 0;
 	}
 
 	nrfx_nvmc_word_write((uint32_t)&NRF_UICR->APPROTECT, UICR_APPROTECT_PALL_Protected);
 	printk("The UICR->APPROTECT register is now configured to deny debugging access for the "
 		   "network core!\n");
 	printk("Success!\n");
+
+	return 0;
 }
diff --git a/samples/tfm/tfm_hello_world/src/main.c b/samples/tfm/tfm_hello_world/src/main.c
index d0c05adcedc6..69463dfb88fd 100644
--- a/samples/tfm/tfm_hello_world/src/main.c
+++ b/samples/tfm/tfm_hello_world/src/main.c
@@ -63,7 +63,7 @@ static void print_hex_number(uint8_t *num, size_t len)
 	printk("\n");
 }
 
-void main(void)
+int main(void)
 {
 	char hello_string[sizeof(HELLO_PATTERN) + sizeof(CONFIG_BOARD)];
 	size_t len;
@@ -149,4 +149,6 @@ void main(void)
 #endif /* defined(CONFIG_TFM_PARTITION_PLATFORM) */
 
 	printk("Finished\n");
+
+	return 0;
 }
diff --git a/samples/tfm/tfm_psa_template/src/main.c b/samples/tfm/tfm_psa_template/src/main.c
index 4ebb986bf9b2..e2d60c794ad6 100644
--- a/samples/tfm/tfm_psa_template/src/main.c
+++ b/samples/tfm/tfm_psa_template/src/main.c
@@ -149,7 +149,7 @@ static void get_attestation_token(void)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int err;
 
diff --git a/samples/tfm/tfm_secure_peripheral/src/main.c b/samples/tfm/tfm_secure_peripheral/src/main.c
index 6c105e7b7c24..85885edcc637 100644
--- a/samples/tfm/tfm_secure_peripheral/src/main.c
+++ b/samples/tfm/tfm_secure_peripheral/src/main.c
@@ -52,7 +52,7 @@ static void send(struct k_work *work)
 	k_work_schedule(&send_work, K_SECONDS(20));
 }
 
-void main(void)
+int main(void)
 {
 	IRQ_CONNECT(EGU0_IRQn, EGU_INT_PRIO, egu0_handler, NULL, 0);
 	nrf_egu_int_enable(NRF_EGU0, NRF_EGU_INT_TRIGGERED0);
@@ -62,4 +62,6 @@ void main(void)
 	k_work_init_delayable(&send_work, send);
 
 	k_work_schedule(&send_work, K_NO_WAIT);
+
+	return 0;
 }
diff --git a/samples/wifi/provisioning/src/main.c b/samples/wifi/provisioning/src/main.c
index 40ff94450215..6f695013efc0 100644
--- a/samples/wifi/provisioning/src/main.c
+++ b/samples/wifi/provisioning/src/main.c
@@ -242,7 +242,7 @@ static void update_dev_name(struct net_linkaddr *mac_addr)
 	byte_to_hex(&device_name[6], mac_addr->addr[5], 'A');
 }
 
-void main(void)
+int main(void)
 {
 	int rc;
 	struct net_if *iface = net_if_get_default();
@@ -257,7 +257,7 @@ void main(void)
 	rc = bt_enable(NULL);
 	if (rc) {
 		printk("Bluetooth init failed (err %d).\n", rc);
-		return;
+		return 0;
 	}
 
 	printk("Bluetooth initialized.\n");
@@ -267,7 +267,7 @@ void main(void)
 		printk("Wi-Fi provisioning service starts successfully.\n");
 	} else {
 		printk("Error occurs when initializing Wi-Fi provisioning service.\n");
-		return;
+		return 0;
 	}
 
 	/* Prepare advertisement data */
@@ -283,7 +283,7 @@ void main(void)
 		ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));
 	if (rc) {
 		printk("BT Advertising failed to start (err %d)\n", rc);
-		return;
+		return 0;
 	}
 	printk("BT Advertising successfully started.\n");
 
@@ -303,4 +303,6 @@ void main(void)
 
 	/* Apply stored wifi credential */
 	net_mgmt(NET_REQUEST_WIFI_CONNECT_STORED, iface, NULL, 0);
+
+	return 0;
 }
diff --git a/samples/wifi/radio_test/src/nrf_wifi_radio_ficr_shell.c b/samples/wifi/radio_test/src/nrf_wifi_radio_ficr_shell.c
index 355d2410d6e5..449f4e6d1d64 100644
--- a/samples/wifi/radio_test/src/nrf_wifi_radio_ficr_shell.c
+++ b/samples/wifi/radio_test/src/nrf_wifi_radio_ficr_shell.c
@@ -271,9 +271,8 @@ SHELL_CMD_REGISTER(wifi_radio_ficr_prog,
 		   NULL);
 
 
-static int nrf_wifi_radio_otp_shell_init(const struct device *unused)
+static int nrf_wifi_radio_otp_shell_init(void)
 {
-	ARG_UNUSED(unused);
 
 	return 0;
 }
diff --git a/samples/wifi/radio_test/src/nrf_wifi_radio_test_main.c b/samples/wifi/radio_test/src/nrf_wifi_radio_test_main.c
index 98a67f0a4892..cf20c6febdb3 100644
--- a/samples/wifi/radio_test/src/nrf_wifi_radio_test_main.c
+++ b/samples/wifi/radio_test/src/nrf_wifi_radio_test_main.c
@@ -6,6 +6,7 @@
 
 #include <zephyr/kernel.h>
 
-void main(void)
+int main(void)
 {
+	return 0;
 }
diff --git a/samples/wifi/radio_test/src/nrf_wifi_radio_test_shell.c b/samples/wifi/radio_test/src/nrf_wifi_radio_test_shell.c
index fdf4fe12d935..edbce0367c8f 100644
--- a/samples/wifi/radio_test/src/nrf_wifi_radio_test_shell.c
+++ b/samples/wifi/radio_test/src/nrf_wifi_radio_test_shell.c
@@ -2375,10 +2375,9 @@ SHELL_CMD_REGISTER(wifi_radio_test,
 		   NULL);
 
 
-static int nrf_wifi_radio_test_shell_init(const struct device *unused)
+static int nrf_wifi_radio_test_shell_init(void)
 {
 	enum wifi_nrf_status status = WIFI_NRF_STATUS_FAIL;
-	ARG_UNUSED(unused);
 
 	status = nrf_wifi_radio_test_conf_init(&ctx->conf_params);
 
diff --git a/samples/wifi/scan/src/main.c b/samples/wifi/scan/src/main.c
index 5abb5d94196c..7f5b4540b271 100644
--- a/samples/wifi/scan/src/main.c
+++ b/samples/wifi/scan/src/main.c
@@ -100,7 +100,7 @@ static int wifi_scan(void)
 	return 0;
 }
 
-void main(void)
+int main(void)
 {
 	scan_result = 0U;
 
@@ -119,4 +119,6 @@ void main(void)
 	LOG_INF("Starting %s with CPU frequency: %d MHz", CONFIG_BOARD, SystemCoreClock / MHZ(1));
 
 	wifi_scan();
+
+	return 0;
 }
diff --git a/samples/wifi/shell/README.rst b/samples/wifi/shell/README.rst
index c6c5b8dccabe..69f373b35aa7 100644
--- a/samples/wifi/shell/README.rst
+++ b/samples/wifi/shell/README.rst
@@ -105,7 +105,7 @@ Supported CLI commands
        | <negotiation_type: 0 - Individual, 1 - Broadcast, 2 - Wake TBTT>
        | <setup_cmd: 0 - Request, 1 - Suggest, 2 - Demand>
        | <dialog_token> <flow_id> <responder> <trigger> <implicit>
-       | <announce> <twt_wake_interval_ms> <twt_interval_ms>
+       | <announce> <twt_wake_interval> <twt_interval>
        |
        | teardown - Teardown a TWT flow:
        | <negotiation_type: 0 - Individual, 1 - Broadcast, 2 - Wake TBTT>
diff --git a/samples/wifi/shell/overlay-zperf.conf b/samples/wifi/shell/overlay-zperf.conf
index 949b13d02317..43eb2e1642bf 100644
--- a/samples/wifi/shell/overlay-zperf.conf
+++ b/samples/wifi/shell/overlay-zperf.conf
@@ -10,6 +10,9 @@ CONFIG_NET_BUF_DATA_SIZE=1100
 CONFIG_NRF700X_QSPI_LOW_POWER=n
 #CONFIG_SPEED_OPTIMIZATIONS=y
 
+# Necessary for zperf_tcp_receiver.c
+CONFIG_NET_CONFIG_SETTINGS=y
+
 # Consumes more memory
 CONFIG_WIFI_CREDENTIALS=n
 CONFIG_FLASH=n
diff --git a/samples/wifi/shell/src/wifi_main.c b/samples/wifi/shell/src/wifi_main.c
index f2aceddca982..6da10cb27df4 100644
--- a/samples/wifi/shell/src/wifi_main.c
+++ b/samples/wifi/shell/src/wifi_main.c
@@ -13,7 +13,7 @@
 #include <zephyr/device.h>
 #include <zephyr/net/net_config.h>
 
-void main(void)
+int main(void)
 {
 #ifdef CLOCK_FEATURE_HFCLK_DIVIDE_PRESENT
 	/* For now hardcode to 128MHz */
@@ -33,4 +33,6 @@ void main(void)
 
 	net_config_init_app(dev, "Initializing network");
 #endif
+
+	return 0;
 }
diff --git a/samples/wifi/sta/src/main.c b/samples/wifi/sta/src/main.c
index e9953749434c..81de12e08b32 100644
--- a/samples/wifi/sta/src/main.c
+++ b/samples/wifi/sta/src/main.c
@@ -280,7 +280,7 @@ int bytes_from_str(const char *str, uint8_t *bytes, size_t bytes_len)
 	return 0;
 }
 
-void main(void)
+int main(void)
 {
 	int i;
 	memset(&context, 0, sizeof(context));
@@ -309,7 +309,7 @@ void main(void)
 		ret = bytes_from_str(CONFIG_NRF700X_QSPI_ENCRYPTION_KEY, key, sizeof(key));
 		if (ret) {
 			LOG_ERR("Failed to parse encryption key: %d\n", ret);
-			return;
+			return 0;
 		}
 
 		LOG_DBG("QSPI Encryption key: ");
@@ -321,7 +321,7 @@ void main(void)
 		ret = qspi_enable_encryption(key);
 		if (ret) {
 			LOG_ERR("Failed to enable encryption: %d\n", ret);
-			return;
+			return 0;
 		}
 		LOG_INF("QSPI Encryption enabled");
 	} else {
@@ -350,4 +350,6 @@ void main(void)
 			LOG_ERR("Connection Timed Out");
 		}
 	}
+
+	return 0;
 }
diff --git a/samples/zigbee/light_bulb/boards/nrf21540dk_nrf52840.overlay b/samples/zigbee/light_bulb/boards/nrf21540dk_nrf52840.overlay
index e27bee37f2de..8c9d4ef533eb 100644
--- a/samples/zigbee/light_bulb/boards/nrf21540dk_nrf52840.overlay
+++ b/samples/zigbee/light_bulb/boards/nrf21540dk_nrf52840.overlay
@@ -10,6 +10,10 @@
 			pwms = <&pwm0 1 PWM_MSEC(20) PWM_POLARITY_INVERTED>;
 		};
 	};
+
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
 };
 
 &pwm0 {
@@ -34,3 +38,7 @@
 	};
 
 };
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/light_bulb/boards/nrf52833dk_nrf52833.overlay b/samples/zigbee/light_bulb/boards/nrf52833dk_nrf52833.overlay
index c4e45e257079..79bc0f3ca58e 100644
--- a/samples/zigbee/light_bulb/boards/nrf52833dk_nrf52833.overlay
+++ b/samples/zigbee/light_bulb/boards/nrf52833dk_nrf52833.overlay
@@ -10,6 +10,10 @@
 			pwms = <&pwm0 1 PWM_MSEC(20) PWM_POLARITY_INVERTED>;
 		};
 	};
+
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
 };
 
 &pwm0 {
@@ -34,3 +38,7 @@
 	};
 
 };
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/light_bulb/boards/nrf52840dk_nrf52840.overlay b/samples/zigbee/light_bulb/boards/nrf52840dk_nrf52840.overlay
index c4e45e257079..79bc0f3ca58e 100644
--- a/samples/zigbee/light_bulb/boards/nrf52840dk_nrf52840.overlay
+++ b/samples/zigbee/light_bulb/boards/nrf52840dk_nrf52840.overlay
@@ -10,6 +10,10 @@
 			pwms = <&pwm0 1 PWM_MSEC(20) PWM_POLARITY_INVERTED>;
 		};
 	};
+
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
 };
 
 &pwm0 {
@@ -34,3 +38,7 @@
 	};
 
 };
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/light_bulb/boards/nrf5340dk_nrf5340_cpuapp.overlay b/samples/zigbee/light_bulb/boards/nrf5340dk_nrf5340_cpuapp.overlay
index 75b7c4ce7d1b..a6f50f3307ac 100644
--- a/samples/zigbee/light_bulb/boards/nrf5340dk_nrf5340_cpuapp.overlay
+++ b/samples/zigbee/light_bulb/boards/nrf5340dk_nrf5340_cpuapp.overlay
@@ -11,6 +11,10 @@
 			pwms = <&pwm0 1 PWM_MSEC(20) PWM_POLARITY_INVERTED>;
 		};
 	};
+
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
 };
 
 &pwm0 {
@@ -35,3 +39,7 @@
 	};
 
 };
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/light_bulb/src/main.c b/samples/zigbee/light_bulb/src/main.c
index 3224de2ffc33..9ebe2c8262fa 100644
--- a/samples/zigbee/light_bulb/src/main.c
+++ b/samples/zigbee/light_bulb/src/main.c
@@ -519,7 +519,7 @@ void zboss_signal_handler(zb_bufid_t bufid)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int blink_status = 0;
 	int err;
diff --git a/samples/zigbee/light_switch/boards/nrf21540dk_nrf52840.overlay b/samples/zigbee/light_switch/boards/nrf21540dk_nrf52840.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/samples/zigbee/light_switch/boards/nrf21540dk_nrf52840.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/light_switch/boards/nrf52833dk_nrf52833.overlay b/samples/zigbee/light_switch/boards/nrf52833dk_nrf52833.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/samples/zigbee/light_switch/boards/nrf52833dk_nrf52833.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/light_switch/boards/nrf52840dk_nrf52840.overlay b/samples/zigbee/light_switch/boards/nrf52840dk_nrf52840.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/samples/zigbee/light_switch/boards/nrf52840dk_nrf52840.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/light_switch/boards/nrf5340dk_nrf5340_cpuapp.overlay b/samples/zigbee/light_switch/boards/nrf5340dk_nrf5340_cpuapp.overlay
index c670799bcdb0..916e83847edb 100644
--- a/samples/zigbee/light_switch/boards/nrf5340dk_nrf5340_cpuapp.overlay
+++ b/samples/zigbee/light_switch/boards/nrf5340dk_nrf5340_cpuapp.overlay
@@ -7,5 +7,10 @@
  / {
 	chosen {
 		nordic,pm-ext-flash = &mx25r64;
+		ncs,zigbee-timer = &timer2;
 	};
 };
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/light_switch/src/main.c b/samples/zigbee/light_switch/src/main.c
index e8c7078ab8f5..d370b432c0a0 100644
--- a/samples/zigbee/light_switch/src/main.c
+++ b/samples/zigbee/light_switch/src/main.c
@@ -722,7 +722,7 @@ static struct nus_entry commands[] = {
 
 #endif /* CONFIG_BT_NUS */
 
-void main(void)
+int main(void)
 {
 	LOG_INF("Starting ZBOSS Light Switch example");
 
diff --git a/samples/zigbee/network_coordinator/boards/nrf21540dk_nrf52840.overlay b/samples/zigbee/network_coordinator/boards/nrf21540dk_nrf52840.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/samples/zigbee/network_coordinator/boards/nrf21540dk_nrf52840.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/network_coordinator/boards/nrf52833dk_nrf52833.overlay b/samples/zigbee/network_coordinator/boards/nrf52833dk_nrf52833.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/samples/zigbee/network_coordinator/boards/nrf52833dk_nrf52833.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/network_coordinator/boards/nrf52840dk_nrf52840.overlay b/samples/zigbee/network_coordinator/boards/nrf52840dk_nrf52840.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/samples/zigbee/network_coordinator/boards/nrf52840dk_nrf52840.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/network_coordinator/boards/nrf5340dk_nrf5340_cpuapp.overlay b/samples/zigbee/network_coordinator/boards/nrf5340dk_nrf5340_cpuapp.overlay
new file mode 100644
index 000000000000..450d810bd387
--- /dev/null
+++ b/samples/zigbee/network_coordinator/boards/nrf5340dk_nrf5340_cpuapp.overlay
@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2022 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+ / {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/network_coordinator/src/main.c b/samples/zigbee/network_coordinator/src/main.c
index db70731ac04f..a96017cfd0a9 100644
--- a/samples/zigbee/network_coordinator/src/main.c
+++ b/samples/zigbee/network_coordinator/src/main.c
@@ -336,7 +336,7 @@ void zboss_signal_handler(zb_bufid_t bufid)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	int blink_status = 0;
 
diff --git a/samples/zigbee/shell/boards/nrf21540dk_nrf52840.overlay b/samples/zigbee/shell/boards/nrf21540dk_nrf52840.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/samples/zigbee/shell/boards/nrf21540dk_nrf52840.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/shell/boards/nrf52833dk_nrf52833.overlay b/samples/zigbee/shell/boards/nrf52833dk_nrf52833.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/samples/zigbee/shell/boards/nrf52833dk_nrf52833.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/shell/boards/nrf52840dk_nrf52840.overlay b/samples/zigbee/shell/boards/nrf52840dk_nrf52840.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/samples/zigbee/shell/boards/nrf52840dk_nrf52840.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/shell/boards/nrf52840dongle_nrf52840.overlay b/samples/zigbee/shell/boards/nrf52840dongle_nrf52840.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/samples/zigbee/shell/boards/nrf52840dongle_nrf52840.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/shell/boards/nrf5340dk_nrf5340_cpuapp.overlay b/samples/zigbee/shell/boards/nrf5340dk_nrf5340_cpuapp.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/samples/zigbee/shell/boards/nrf5340dk_nrf5340_cpuapp.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/shell/sample.yaml b/samples/zigbee/shell/sample.yaml
index 46de9d8cc411..5670e1f835f2 100644
--- a/samples/zigbee/shell/sample.yaml
+++ b/samples/zigbee/shell/sample.yaml
@@ -12,15 +12,48 @@ tests:
     platform_allow: nrf52840dk_nrf52840 nrf52833dk_nrf52833 nrf5340dk_nrf5340_cpuapp
       nrf21540dk_nrf52840
     tags: ci_build shell
-  sample.zigbee.shell.usb:
+  sample.zigbee.shell.usb.nrf52840dk_nrf52840:
     build_only: true
-    extra_args: CONF_FILE=prj_usb.conf
+    extra_args:
+      CONF_FILE=prj_usb.conf
+      DTC_OVERLAY_FILE="app_usb.overlay;boards/nrf52840dk_nrf52840.overlay"
     integration_platforms:
       - nrf52840dk_nrf52840
-      - nrf52833dk_nrf52833
-      - nrf5340dk_nrf5340_cpuapp
+    platform_allow: nrf52840dk_nrf52840
+    tags: ci_build shell
+  sample.zigbee.shell.usb.nrf21540dk_nrf52840:
+    build_only: true
+    extra_args:
+      CONF_FILE=prj_usb.conf
+      DTC_OVERLAY_FILE="app_usb.overlay;boards/nrf21540dk_nrf52840.overlay"
+    integration_platforms:
       - nrf21540dk_nrf52840
+    platform_allow: nrf21540dk_nrf52840
+    tags: ci_build shell
+  sample.zigbee.shell.usb.nrf52833dk_nrf52833:
+    build_only: true
+    extra_args:
+      CONF_FILE=prj_usb.conf
+      DTC_OVERLAY_FILE="app_usb.overlay;boards/nrf52833dk_nrf52833.overlay"
+    integration_platforms:
+      - nrf52833dk_nrf52833
+    platform_allow: nrf52833dk_nrf52833
+    tags: ci_build shell
+  sample.zigbee.shell.usb.nrf52840dongle_nrf52840:
+    build_only: true
+    extra_args:
+      CONF_FILE=prj_usb.conf
+      DTC_OVERLAY_FILE="app_usb.overlay;boards/nrf52840dongle_nrf52840.overlay"
+    integration_platforms:
       - nrf52840dongle_nrf52840
-    platform_allow: nrf52840dk_nrf52840 nrf52833dk_nrf52833 nrf5340dk_nrf5340_cpuapp
-      nrf21540dk_nrf52840 nrf52840dongle_nrf52840
+    platform_allow: nrf52840dongle_nrf52840
+    tags: ci_build shell
+  sample.zigbee.shell.usb.nrf5340dk_nrf5340_cpuapp:
+    build_only: true
+    extra_args:
+      CONF_FILE=prj_usb.conf
+      DTC_OVERLAY_FILE="app_usb.overlay;boards/nrf5340dk_nrf5340_cpuapp.overlay"
+    integration_platforms:
+      - nrf5340dk_nrf5340_cpuapp
+    platform_allow: nrf5340dk_nrf5340_cpuapp
     tags: ci_build shell
diff --git a/samples/zigbee/shell/src/main.c b/samples/zigbee/shell/src/main.c
index 61e340fb6726..b058bc2ca435 100644
--- a/samples/zigbee/shell/src/main.c
+++ b/samples/zigbee/shell/src/main.c
@@ -233,7 +233,7 @@ void zboss_signal_handler(zb_bufid_t bufid)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	LOG_INF("Starting Zigbee shell application");
 
@@ -249,4 +249,6 @@ void main(void)
 	ZB_AF_SET_IDENTIFY_NOTIFICATION_HANDLER(APP_ZIGBEE_ENDPOINT, identify_cb);
 
 	LOG_INF("Zigbee shell application started");
+
+	return 0;
 }
diff --git a/samples/zigbee/template/boards/nrf21540dk_nrf52840.overlay b/samples/zigbee/template/boards/nrf21540dk_nrf52840.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/samples/zigbee/template/boards/nrf21540dk_nrf52840.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/template/boards/nrf52833dk_nrf52833.overlay b/samples/zigbee/template/boards/nrf52833dk_nrf52833.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/samples/zigbee/template/boards/nrf52833dk_nrf52833.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/template/boards/nrf52840dk_nrf52840.overlay b/samples/zigbee/template/boards/nrf52840dk_nrf52840.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/samples/zigbee/template/boards/nrf52840dk_nrf52840.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/template/boards/nrf5340dk_nrf5340_cpuapp.overlay b/samples/zigbee/template/boards/nrf5340dk_nrf5340_cpuapp.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/samples/zigbee/template/boards/nrf5340dk_nrf5340_cpuapp.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/samples/zigbee/template/src/main.c b/samples/zigbee/template/src/main.c
index 466983293ebd..27b88f4113bc 100644
--- a/samples/zigbee/template/src/main.c
+++ b/samples/zigbee/template/src/main.c
@@ -222,7 +222,7 @@ void zboss_signal_handler(zb_bufid_t bufid)
 	}
 }
 
-void main(void)
+int main(void)
 {
 	LOG_INF("Starting Zigbee application template example");
 
@@ -242,4 +242,6 @@ void main(void)
 	zigbee_enable();
 
 	LOG_INF("Zigbee application template started");
+
+	return 0;
 }
diff --git a/scripts/ci/license_allow_list.yaml b/scripts/ci/license_allow_list.yaml
index edfe4aa81734..1986521abf34 100644
--- a/scripts/ci/license_allow_list.yaml
+++ b/scripts/ci/license_allow_list.yaml
@@ -42,6 +42,7 @@ LicenseRef-west-ncs-sbom-iperf-BSD-3-Clause: "^nrf/ext/"
 Apache-2.0: |
   ^nrf/ext/
   /src/zap-generated/
+  ^nrf/tests/bluetooth/tester/src/main.c$
 curl: "^nrf/ext/"
 MIT: "^nrf/ext/"
 BSD-3-CLAUSE: "^nrf/ext/"
diff --git a/scripts/quarantine.yaml b/scripts/quarantine.yaml
index 862747555bbc..cb94e500e21e 100644
--- a/scripts/quarantine.yaml
+++ b/scripts/quarantine.yaml
@@ -108,3 +108,20 @@
   platforms:
     - thingy53_nrf5340_cpuapp
   comment: "Configurations excluded to limit resources usage in integration builds"
+
+- scenarios:
+    - sample.ant_advanced_burst
+    - sample.ant_background_scanning
+    - sample.ant_broadcast_rx
+    - sample.ant_broadcast_tx
+    - sample.bpwr_rx
+    - sample.bpwr_tx
+    - sample.bsc_rx
+    - sample.bsc_tx
+    - sample.hrm_rx
+    - sample.hrm_tx
+    - sample.ble_ant_app_hrm
+    - sample.ant_rpc
+  platforms:
+    - all
+  comment: "ANT samples fail to build; need to change main()'s signature to int main(void)"
diff --git a/subsys/bluetooth/Kconfig.discovery b/subsys/bluetooth/Kconfig.discovery
index 7229a0ab3054..ec6b8d541bd3 100644
--- a/subsys/bluetooth/Kconfig.discovery
+++ b/subsys/bluetooth/Kconfig.discovery
@@ -19,7 +19,6 @@ config BT_GATT_DM_MAX_ATTRS
 
 config BT_GATT_DM_DATA_PRINT
 	bool "Enable functions for printing discovery related data"
-	depends on BT_DEBUG
 	help
 	  Enable functions for printing discovery related data
 
diff --git a/subsys/bluetooth/Kconfig.enocean b/subsys/bluetooth/Kconfig.enocean
index 2ad7843f599f..3a3da67bda65 100644
--- a/subsys/bluetooth/Kconfig.enocean
+++ b/subsys/bluetooth/Kconfig.enocean
@@ -59,19 +59,8 @@ endif
 
 endif
 
-config BT_ENOCEAN_DEBUG
-	bool "Enable debug logs"
-	depends on BT_DEBUG
-	help
-	  Use this option to enable debug logs for the Bluetooth
-	  Enocean functionality.
-
-if BT_ENOCEAN_DEBUG
-
 module = BT_ENOCEAN
 module-str = EnOcean library
 source "${ZEPHYR_BASE}/subsys/logging/Kconfig.template.log_config"
 
 endif
-
-endif
diff --git a/subsys/bluetooth/controller/hci_driver.c b/subsys/bluetooth/controller/hci_driver.c
index e00183bc6d08..cd1d68bd9439 100644
--- a/subsys/bluetooth/controller/hci_driver.c
+++ b/subsys/bluetooth/controller/hci_driver.c
@@ -1033,9 +1033,8 @@ void bt_ctlr_set_public_addr(const uint8_t *addr)
 	(void)sdc_hci_cmd_vs_zephyr_write_bd_addr(bd_addr);
 }
 
-static int hci_driver_init(const struct device *unused)
+static int hci_driver_init(void)
 {
-	ARG_UNUSED(unused);
 	int err = 0;
 
 	bt_hci_driver_register(&drv);
diff --git a/subsys/bluetooth/mesh/lightness_internal.h b/subsys/bluetooth/mesh/lightness_internal.h
index 621d6f5b098e..498864a4c464 100644
--- a/subsys/bluetooth/mesh/lightness_internal.h
+++ b/subsys/bluetooth/mesh/lightness_internal.h
@@ -93,7 +93,7 @@ static inline uint16_t actual_to_linear(uint16_t actual)
 	/* Conversion:
 	 * linear = CEIL(65535 * (actual * actual) / (65535 * 65535)))
 	 */
-	return ceiling_fraction((uint32_t)actual * (uint32_t)actual, 65535UL);
+	return DIV_ROUND_UP((uint32_t)actual * (uint32_t)actual, 65535UL);
 }
 
 /** @brief Convert light from the specified representation to the configured.
diff --git a/subsys/bluetooth/mesh/scheduler_srv.c b/subsys/bluetooth/mesh/scheduler_srv.c
index d4d7aa340426..07f7debdc270 100644
--- a/subsys/bluetooth/mesh/scheduler_srv.c
+++ b/subsys/bluetooth/mesh/scheduler_srv.c
@@ -237,11 +237,11 @@ static int minute_handler(struct tm *sched_time, struct tm *current_local,
 	bool minute_ovflw = false;
 
 	if (entry->minute == BT_MESH_SCHEDULER_EVERY_15_MINUTES) {
-		info->start_minute = 15 * ceiling_fraction(current_local->tm_min + 1, 15);
+		info->start_minute = 15 * DIV_ROUND_UP(current_local->tm_min + 1, 15);
 		minute_ovflw = info->start_minute == 60;
 		sched_time->tm_min = minute_ovflw ? 0 : info->start_minute;
 	} else if (entry->minute == BT_MESH_SCHEDULER_EVERY_20_MINUTES) {
-		info->start_minute = 20 * ceiling_fraction(current_local->tm_min + 1, 20);
+		info->start_minute = 20 * DIV_ROUND_UP(current_local->tm_min + 1, 20);
 		minute_ovflw = info->start_minute == 60;
 		sched_time->tm_min = minute_ovflw ? 0 : info->start_minute;
 	} else if (entry->minute == BT_MESH_SCHEDULER_ONCE_AN_HOUR) {
@@ -273,11 +273,11 @@ static int second_handler(struct tm *sched_time, struct tm *current_local,
 	bool second_ovflw = false;
 
 	if (entry->second == BT_MESH_SCHEDULER_EVERY_15_SECONDS) {
-		info->start_second = 15 * ceiling_fraction(current_local->tm_sec + 1, 15);
+		info->start_second = 15 * DIV_ROUND_UP(current_local->tm_sec + 1, 15);
 		second_ovflw = info->start_second == 60;
 		sched_time->tm_sec = second_ovflw ? 0 : info->start_second;
 	} else if (entry->second == BT_MESH_SCHEDULER_EVERY_20_SECONDS) {
-		info->start_second = 20 * ceiling_fraction(current_local->tm_sec + 1, 20);
+		info->start_second = 20 * DIV_ROUND_UP(current_local->tm_sec + 1, 20);
 		second_ovflw = info->start_second == 60;
 		sched_time->tm_sec = second_ovflw ? 0 : info->start_second;
 	} else if (entry->second == BT_MESH_SCHEDULER_ONCE_A_MINUTE) {
diff --git a/subsys/bluetooth/mesh/sensor_srv.c b/subsys/bluetooth/mesh/sensor_srv.c
index 2ab88390b283..214203ea61ae 100644
--- a/subsys/bluetooth/mesh/sensor_srv.c
+++ b/subsys/bluetooth/mesh/sensor_srv.c
@@ -861,7 +861,7 @@ static uint16_t min_int_get(const struct bt_mesh_sensor *sensor,
 	uint32_t pub_int = (base_period >> period_div);
 	uint32_t min_int = (1 << sensor->state.min_int);
 
-	return ceiling_fraction(min_int, pub_int);
+	return DIV_ROUND_UP(min_int, pub_int);
 }
 
 /** @brief Conditionally add a sensor value to a publication.
diff --git a/subsys/bluetooth/rpc/client/bt_rpc_conn_client.c b/subsys/bluetooth/rpc/client/bt_rpc_conn_client.c
index 545e716c3287..934aab7fbe05 100644
--- a/subsys/bluetooth/rpc/client/bt_rpc_conn_client.c
+++ b/subsys/bluetooth/rpc/client/bt_rpc_conn_client.c
@@ -1175,7 +1175,7 @@ void bt_set_bondable(bool enable)
 				&ctx, ser_rsp_decode_void, NULL);
 }
 
-void bt_set_oob_data_flag(bool enable)
+void bt_le_oob_set_legacy_flag(bool enable)
 {
 	struct nrf_rpc_cbor_ctx ctx;
 	size_t buffer_size_max = 1;
@@ -1184,7 +1184,20 @@ void bt_set_oob_data_flag(bool enable)
 
 	ser_encode_bool(&ctx, enable);
 
-	nrf_rpc_cbor_cmd_no_err(&bt_rpc_grp, BT_SET_OOB_DATA_FLAG_RPC_CMD,
+	nrf_rpc_cbor_cmd_no_err(&bt_rpc_grp, BT_LE_OOB_SET_LEGACY_FLAG_RPC_CMD,
+				&ctx, ser_rsp_decode_void, NULL);
+}
+
+void bt_le_oob_set_sc_flag(bool enable)
+{
+	struct nrf_rpc_cbor_ctx ctx;
+	size_t buffer_size_max = 1;
+
+	NRF_RPC_CBOR_ALLOC(&bt_rpc_grp, ctx, buffer_size_max);
+
+	ser_encode_bool(&ctx, enable);
+
+	nrf_rpc_cbor_cmd_no_err(&bt_rpc_grp, BT_LE_OOB_SET_SC_FLAG_RPC_CMD,
 				&ctx, ser_rsp_decode_void, NULL);
 }
 
diff --git a/subsys/bluetooth/rpc/common/bt_rpc_common.c b/subsys/bluetooth/rpc/common/bt_rpc_common.c
index def3af09562f..ee089195aaaa 100644
--- a/subsys/bluetooth/rpc/common/bt_rpc_common.c
+++ b/subsys/bluetooth/rpc/common/bt_rpc_common.c
@@ -30,9 +30,8 @@ static void err_handler(const struct nrf_rpc_err_report *report)
 	k_oops();
 }
 
-static int serialization_init(const struct device *dev)
+static int serialization_init(void)
 {
-	ARG_UNUSED(dev);
 
 	int err;
 
diff --git a/subsys/bluetooth/rpc/common/bt_rpc_common.h b/subsys/bluetooth/rpc/common/bt_rpc_common.h
index 0d76873c3d62..235d5e3a720e 100644
--- a/subsys/bluetooth/rpc/common/bt_rpc_common.h
+++ b/subsys/bluetooth/rpc/common/bt_rpc_common.h
@@ -98,7 +98,8 @@ enum bt_rpc_cmd_from_cli_to_host {
 	BT_CONN_ENC_KEY_SIZE_RPC_CMD,
 	BT_CONN_CB_REGISTER_ON_REMOTE_RPC_CMD,
 	BT_SET_BONDABLE_RPC_CMD,
-	BT_SET_OOB_DATA_FLAG_RPC_CMD,
+	BT_LE_OOB_SET_LEGACY_FLAG_RPC_CMD,
+	BT_LE_OOB_SET_SC_FLAG_RPC_CMD,
 	BT_LE_OOB_SET_LEGACY_TK_RPC_CMD,
 	BT_LE_OOB_SET_SC_DATA_RPC_CMD,
 	BT_LE_OOB_GET_SC_DATA_RPC_CMD,
diff --git a/subsys/bluetooth/rpc/host/bt_rpc_conn_host.c b/subsys/bluetooth/rpc/host/bt_rpc_conn_host.c
index 4cd96e2c28cf..e62d1aa3cc4b 100644
--- a/subsys/bluetooth/rpc/host/bt_rpc_conn_host.c
+++ b/subsys/bluetooth/rpc/host/bt_rpc_conn_host.c
@@ -964,7 +964,7 @@ NRF_RPC_CBOR_CMD_DECODER(bt_rpc_grp, bt_set_bondable, BT_SET_BONDABLE_RPC_CMD,
 			 bt_set_bondable_rpc_handler, NULL);
 
 
-static void bt_set_oob_data_flag_rpc_handler(const struct nrf_rpc_group *group,
+static void bt_le_oob_set_legacy_flag_rpc_handler(const struct nrf_rpc_group *group,
 					     struct nrf_rpc_cbor_ctx *ctx, void *handler_data)
 {
 	bool enable;
@@ -975,17 +975,42 @@ static void bt_set_oob_data_flag_rpc_handler(const struct nrf_rpc_group *group,
 		goto decoding_error;
 	}
 
-	bt_set_oob_data_flag(enable);
+	bt_le_oob_set_legacy_flag(enable);
 
 	ser_rsp_send_void(group);
 
 	return;
 decoding_error:
-	report_decoding_error(BT_SET_OOB_DATA_FLAG_RPC_CMD, handler_data);
+	report_decoding_error(BT_LE_OOB_SET_LEGACY_FLAG_RPC_CMD, handler_data);
 }
 
-NRF_RPC_CBOR_CMD_DECODER(bt_rpc_grp, bt_set_oob_data_flag, BT_SET_OOB_DATA_FLAG_RPC_CMD,
-			 bt_set_oob_data_flag_rpc_handler, NULL);
+NRF_RPC_CBOR_CMD_DECODER(bt_rpc_grp, bt_le_oob_set_legacy_flag, BT_LE_OOB_SET_LEGACY_FLAG_RPC_CMD,
+			 bt_le_oob_set_legacy_flag_rpc_handler, NULL);
+
+
+static void bt_le_oob_set_sc_flag_rpc_handler(const struct nrf_rpc_group *group,
+					     struct nrf_rpc_cbor_ctx *ctx, void *handler_data)
+{
+	bool enable;
+
+	enable = ser_decode_bool(ctx);
+
+	if (!ser_decoding_done_and_check(group, ctx)) {
+		goto decoding_error;
+	}
+
+	bt_le_oob_set_sc_flag(enable);
+
+	ser_rsp_send_void(group);
+
+	return;
+decoding_error:
+	report_decoding_error(BT_LE_OOB_SET_SC_FLAG_RPC_CMD, handler_data);
+}
+
+NRF_RPC_CBOR_CMD_DECODER(bt_rpc_grp, bt_le_oob_set_sc_flag, BT_LE_OOB_SET_SC_FLAG_RPC_CMD,
+			 bt_le_oob_set_sc_flag_rpc_handler, NULL);
+
 
 #if !defined(CONFIG_BT_SMP_SC_PAIR_ONLY)
 static void bt_le_oob_set_legacy_tk_rpc_handler(const struct nrf_rpc_group *group,
diff --git a/subsys/bluetooth/rpc/host/bt_rpc_gatt_host.c b/subsys/bluetooth/rpc/host/bt_rpc_gatt_host.c
index 716995d98396..43c8ff11f620 100644
--- a/subsys/bluetooth/rpc/host/bt_rpc_gatt_host.c
+++ b/subsys/bluetooth/rpc/host/bt_rpc_gatt_host.c
@@ -79,7 +79,7 @@ static struct bt_uuid const * const uuid_cep = BT_UUID_GATT_CEP;
 static struct bt_uuid const * const uuid_cud = BT_UUID_GATT_CUD;
 static struct bt_uuid const * const uuid_cpf = BT_UUID_GATT_CPF;
 
-static uint32_t gatt_buffer_data[ceiling_fraction(CONFIG_BT_RPC_GATT_BUFFER_SIZE,
+static uint32_t gatt_buffer_data[DIV_ROUND_UP(CONFIG_BT_RPC_GATT_BUFFER_SIZE,
 						  sizeof(uint32_t))];
 static struct net_buf_simple gatt_buffer = {
 	.data = (uint8_t *)gatt_buffer_data,
diff --git a/subsys/bluetooth/services/fast_pair/fp_keys.c b/subsys/bluetooth/services/fast_pair/fp_keys.c
index 7ddc50264dff..5725fbf1b4f1 100644
--- a/subsys/bluetooth/services/fast_pair/fp_keys.c
+++ b/subsys/bluetooth/services/fast_pair/fp_keys.c
@@ -442,9 +442,8 @@ static void timeout_fn(struct k_work *w)
 	key_timeout(proc);
 }
 
-static int fp_keys_init(const struct device *unused)
+static int fp_keys_init(void)
 {
-	ARG_UNUSED(unused);
 
 	for (size_t i = 0; i < ARRAY_SIZE(fp_procedures); i++) {
 		struct fp_procedure *proc = &fp_procedures[i];
diff --git a/subsys/bluetooth/services/fast_pair/fp_registration_data.c b/subsys/bluetooth/services/fast_pair/fp_registration_data.c
index 36416af14ac6..a926be36800c 100644
--- a/subsys/bluetooth/services/fast_pair/fp_registration_data.c
+++ b/subsys/bluetooth/services/fast_pair/fp_registration_data.c
@@ -111,9 +111,8 @@ static int validate_fp_hash(const uint8_t *prov_data, const uint8_t *hash)
 	return err;
 }
 
-static int fp_registration_data_validate(const struct device *unused)
+static int fp_registration_data_validate(void)
 {
-	ARG_UNUSED(unused);
 
 	int err;
 	uint8_t data[FP_DATA_SIZE];
diff --git a/subsys/caf/modules/sensor_data_aggregator.c b/subsys/caf/modules/sensor_data_aggregator.c
index 058dda533b05..9717c3b46616 100644
--- a/subsys/caf/modules/sensor_data_aggregator.c
+++ b/subsys/caf/modules/sensor_data_aggregator.c
@@ -29,7 +29,7 @@ LOG_MODULE_REGISTER(MODULE, CONFIG_CAF_SENSOR_DATA_AGGREGATOR_LOG_LEVEL);
 #define __DATA_BUFF_NAME(agg_node, n) DT_CAT5(agg_, agg_node,  _buff_,  n,  _data)
 #define __DEFINE_DATA(n, agg_node, size)                         \
 	static struct sensor_value __DATA_BUFF_NAME(agg_node, n) \
-		[ceiling_fraction(size, sizeof(struct sensor_value))]
+		[DIV_ROUND_UP(size, sizeof(struct sensor_value))]
 /* End of BSS version only macros. */
 
 #define __INITIALIZE_BUFF(n, agg_node)                                                        \
diff --git a/subsys/caf/modules/sensor_manager.c b/subsys/caf/modules/sensor_manager.c
index 27cf1ec07e95..309cd169ab68 100644
--- a/subsys/caf/modules/sensor_manager.c
+++ b/subsys/caf/modules/sensor_manager.c
@@ -111,7 +111,7 @@ static void reset_sensor_sleep_cnt(const struct sm_sensor_config *sc,
 	unsigned int timeout = sc->trigger->activation.timeout_ms;
 	unsigned int period = sc->sampling_period_ms;
 
-	sd->sleep_cntd = ceiling_fraction(timeout, period);
+	sd->sleep_cntd = DIV_ROUND_UP(timeout, period);
 }
 
 static bool process_sensor_trigger_values(const struct sm_sensor_config *sc, struct sensor_data *sd,
diff --git a/subsys/caf/modules/settings_loader.c b/subsys/caf/modules/settings_loader.c
index 8894d1b13842..e6347c7a9c83 100644
--- a/subsys/caf/modules/settings_loader.c
+++ b/subsys/caf/modules/settings_loader.c
@@ -116,9 +116,8 @@ static bool app_event_handler(const struct app_event_header *aeh)
 APP_EVENT_LISTENER(MODULE, app_event_handler);
 APP_EVENT_SUBSCRIBE(MODULE, module_state_event);
 
-static int caf_settings_init(const struct device *unused)
+static int caf_settings_init(void)
 {
-	ARG_UNUSED(unused);
 
 	/* Initialize settings subsystem on system start to ensure that the subsystem is initialized
 	 * before the application starts using it (e.g. before registering runtime handlers).
diff --git a/subsys/debug/cpu_load/Kconfig b/subsys/debug/cpu_load/Kconfig
index cb4850999d27..9b6250be6b0a 100644
--- a/subsys/debug/cpu_load/Kconfig
+++ b/subsys/debug/cpu_load/Kconfig
@@ -67,23 +67,23 @@ choice
 	default CPU_LOAD_TIMER_2
 
 config CPU_LOAD_TIMER_0
-	depends on HAS_HW_NRF_TIMER0
+	depends on $(dt_nodelabel_has_compat,timer0,$(DT_COMPAT_NORDIC_NRF_TIMER))
 	bool "Timer 0"
 	select NRFX_TIMER0
 config CPU_LOAD_TIMER_1
-	depends on HAS_HW_NRF_TIMER1
+	depends on $(dt_nodelabel_has_compat,timer1,$(DT_COMPAT_NORDIC_NRF_TIMER))
 	bool "Timer 1"
 	select NRFX_TIMER1
 config CPU_LOAD_TIMER_2
-	depends on HAS_HW_NRF_TIMER2
+	depends on $(dt_nodelabel_has_compat,timer2,$(DT_COMPAT_NORDIC_NRF_TIMER))
 	bool "Timer 2"
 	select NRFX_TIMER2
 config CPU_LOAD_TIMER_3
-	depends on HAS_HW_NRF_TIMER3
+	depends on $(dt_nodelabel_has_compat,timer3,$(DT_COMPAT_NORDIC_NRF_TIMER))
 	bool "Timer 3"
 	select NRFX_TIMER3
 config CPU_LOAD_TIMER_4
-	depends on HAS_HW_NRF_TIMER4
+	depends on $(dt_nodelabel_has_compat,timer4,$(DT_COMPAT_NORDIC_NRF_TIMER))
 	bool "Timer 4"
 	select NRFX_TIMER4
 
diff --git a/subsys/dm/Kconfig b/subsys/dm/Kconfig
index 4ead55b10d02..299390c50b8d 100644
--- a/subsys/dm/Kconfig
+++ b/subsys/dm/Kconfig
@@ -15,32 +15,6 @@ if DM_MODULE
 
 menu "nRF DM (Distance Measurement)"
 
-choice DM_TIMER
-	default DM_TIMER2
-	prompt "Timer to use for the nrf_dm library."
-
-config DM_TIMER0
-	depends on HAS_HW_NRF_TIMER0
-	bool "TIMER0"
-
-config DM_TIMER1
-	depends on HAS_HW_NRF_TIMER1
-	bool "TIMER1"
-
-config DM_TIMER2
-	depends on HAS_HW_NRF_TIMER2
-	bool "TIMER2"
-
-config DM_TIMER3
-	depends on HAS_HW_NRF_TIMER3
-	bool "TIMER3"
-
-config DM_TIMER4
-	depends on HAS_HW_NRF_TIMER4
-	bool "TIMER4"
-
-endchoice
-
 config DM_HIGH_PRECISION_CALC
 	# Due to memory limitations, functionality is not provided for nrf52832.
 	depends on !SOC_NRF52832
diff --git a/subsys/dm/dm.c b/subsys/dm/dm.c
index dab96255895e..1d2567a07a98 100644
--- a/subsys/dm/dm.c
+++ b/subsys/dm/dm.c
@@ -37,21 +37,12 @@
 
 LOG_MODULE_REGISTER(nrf_dm, CONFIG_DM_MODULE_LOG_LEVEL);
 
-#ifdef CONFIG_DM_TIMER0
-#define DM_TIMER NRF_TIMER0
-#endif
-#ifdef CONFIG_DM_TIMER1
-#define DM_TIMER NRF_TIMER1
-#endif
-#ifdef CONFIG_DM_TIMER2
+#if DT_HAS_CHOSEN(ncs_dm_timer)
+#define DM_TIMER ((NRF_TIMER_Type *)DT_REG_ADDR(DT_CHOSEN(ncs_dm_timer)))
+#else
+#warning "The ncs,dm-timer chosen node is not set; defaulting to TIMER2"
 #define DM_TIMER NRF_TIMER2
 #endif
-#ifdef CONFIG_DM_TIMER3
-#define DM_TIMER NRF_TIMER3
-#endif
-#ifdef CONFIG_DM_TIMER4
-#define DM_TIMER NRF_TIMER4
-#endif
 
 #define PPI_CH_COUNT                 2
 
diff --git a/subsys/dm/rpc/client/dm_rpc_client.c b/subsys/dm/rpc/client/dm_rpc_client.c
index 2f3e35f133ef..7690245b18f7 100644
--- a/subsys/dm/rpc/client/dm_rpc_client.c
+++ b/subsys/dm/rpc/client/dm_rpc_client.c
@@ -164,9 +164,8 @@ static void data_handler(struct k_work *work)
 	ipc_service_send(&ep, &cmd, sizeof(cmd));
 }
 
-static int ipc_init(const struct device *dev)
+static int ipc_init(void)
 {
-	ARG_UNUSED(dev);
 
 	int err;
 	const struct device *ipc_instance;
diff --git a/subsys/dm/rpc/common/dm_rpc_common.c b/subsys/dm/rpc/common/dm_rpc_common.c
index 7ecbe564a1d5..f63d5d6c149a 100644
--- a/subsys/dm/rpc/common/dm_rpc_common.c
+++ b/subsys/dm/rpc/common/dm_rpc_common.c
@@ -27,9 +27,8 @@ static void err_handler(const struct nrf_rpc_err_report *report)
 	k_oops();
 }
 
-static int serialization_init(const struct device *dev)
+static int serialization_init(void)
 {
-	ARG_UNUSED(dev);
 
 	int err;
 
diff --git a/subsys/dm/rpc/host/dm_rpc_host.c b/subsys/dm/rpc/host/dm_rpc_host.c
index f12094323b9b..9971d06ae0d2 100644
--- a/subsys/dm/rpc/host/dm_rpc_host.c
+++ b/subsys/dm/rpc/host/dm_rpc_host.c
@@ -123,9 +123,8 @@ static struct ipc_ept_cfg ep_cfg = {
 	},
 };
 
-static int ipc_init(const struct device *dev)
+static int ipc_init(void)
 {
-	ARG_UNUSED(dev);
 
 	int err;
 	const struct device *ipc_instance;
diff --git a/subsys/esb/Kconfig b/subsys/esb/Kconfig
index 8918a5845011..9edbebdc2243 100644
--- a/subsys/esb/Kconfig
+++ b/subsys/esb/Kconfig
@@ -65,27 +65,27 @@ choice ESB_SYS_TIMER
 
 config ESB_SYS_TIMER0
 	bool "TIMER0"
-	depends on HAS_HW_NRF_TIMER0
+	depends on $(dt_nodelabel_has_compat,timer0,$(DT_COMPAT_NORDIC_NRF_TIMER))
 	select NRFX_TIMER0
 
 config ESB_SYS_TIMER1
 	bool "TIMER1"
-	depends on HAS_HW_NRF_TIMER1
+	depends on $(dt_nodelabel_has_compat,timer1,$(DT_COMPAT_NORDIC_NRF_TIMER))
 	select NRFX_TIMER1
 
 config ESB_SYS_TIMER2
 	bool "TIMER2"
-	depends on HAS_HW_NRF_TIMER2
+	depends on $(dt_nodelabel_has_compat,timer2,$(DT_COMPAT_NORDIC_NRF_TIMER))
 	select NRFX_TIMER2
 
 config ESB_SYS_TIMER3
 	bool "TIMER3"
-	depends on HAS_HW_NRF_TIMER3
+	depends on $(dt_nodelabel_has_compat,timer3,$(DT_COMPAT_NORDIC_NRF_TIMER))
 	select NRFX_TIMER3
 
 config ESB_SYS_TIMER4
 	bool "TIMER4"
-	depends on HAS_HW_NRF_TIMER4
+	depends on $(dt_nodelabel_has_compat,timer4,$(DT_COMPAT_NORDIC_NRF_TIMER))
 	select NRFX_TIMER4
 
 endchoice
diff --git a/subsys/event_manager_proxy/event_manager_proxy.c b/subsys/event_manager_proxy/event_manager_proxy.c
index 5eeb885af13c..2c151727ba16 100644
--- a/subsys/event_manager_proxy/event_manager_proxy.c
+++ b/subsys/event_manager_proxy/event_manager_proxy.c
@@ -284,7 +284,7 @@ static int send_event_to_remote(struct emp_ipc_data *ipc, const struct app_event
 	}
 
 	size_t size = app_event_manager_event_size(eh);
-	uint32_t buffer[ceiling_fraction(size, sizeof(uint32_t))];
+	uint32_t buffer[DIV_ROUND_UP(size, sizeof(uint32_t))];
 	struct app_event_header *remote_eh = (struct app_event_header *)buffer;
 
 	memcpy(buffer, eh, sizeof(buffer));
@@ -400,7 +400,7 @@ static int send_subscribe_command_to_remote(struct emp_ipc_data *ipc,
 	/* Preparing and sending the command */
 	struct emp_cmd_subscribe *cmd;
 	size_t size = sizeof(*cmd) + strlen(remote_event_name) + 1;
-	uint32_t buffer[ceiling_fraction(size, sizeof(uint32_t))];
+	uint32_t buffer[DIV_ROUND_UP(size, sizeof(uint32_t))];
 
 	cmd = (struct emp_cmd_subscribe *)buffer;
 	cmd->code = EMP_CMD_SUBSCRIBE;
diff --git a/subsys/fw_info/fw_info.c b/subsys/fw_info/fw_info.c
index d2c5032ba58d..a0292a2962f2 100644
--- a/subsys/fw_info/fw_info.c
+++ b/subsys/fw_info/fw_info.c
@@ -168,10 +168,8 @@ EXT_API(EXT_API_PROVIDE, struct ext_api_provide_ext_api,
 };
 #endif
 
-static int check_ext_api_requests(const struct device *dev)
+static int check_ext_api_requests(void)
 {
-	(void)dev;
-
 	const struct fw_info_ext_api_request *ext_api_req =
 			skip_ext_apis(&m_firmware_info);
 
diff --git a/subsys/gazell/Kconfig b/subsys/gazell/Kconfig
index 08bc9d4762d6..d3f2f5eba446 100644
--- a/subsys/gazell/Kconfig
+++ b/subsys/gazell/Kconfig
@@ -109,23 +109,23 @@ choice GAZELL_TIMER
 
 config GAZELL_TIMER0
 	bool "TIMER0"
-	depends on HAS_HW_NRF_TIMER0
+	depends on $(dt_nodelabel_has_compat,timer0,$(DT_COMPAT_NORDIC_NRF_TIMER))
 
 config GAZELL_TIMER1
 	bool "TIMER1"
-	depends on HAS_HW_NRF_TIMER1
+	depends on $(dt_nodelabel_has_compat,timer1,$(DT_COMPAT_NORDIC_NRF_TIMER))
 
 config GAZELL_TIMER2
 	bool "TIMER2"
-	depends on HAS_HW_NRF_TIMER2
+	depends on $(dt_nodelabel_has_compat,timer2,$(DT_COMPAT_NORDIC_NRF_TIMER))
 
 config GAZELL_TIMER3
 	bool "TIMER3"
-	depends on HAS_HW_NRF_TIMER3
+	depends on $(dt_nodelabel_has_compat,timer3,$(DT_COMPAT_NORDIC_NRF_TIMER))
 
 config GAZELL_TIMER4
 	bool "TIMER4"
-	depends on HAS_HW_NRF_TIMER4
+	depends on $(dt_nodelabel_has_compat,timer4,$(DT_COMPAT_NORDIC_NRF_TIMER))
 
 endchoice
 
diff --git a/subsys/ieee802154/nrf_802154_configurator.c b/subsys/ieee802154/nrf_802154_configurator.c
index 394d6aae2e81..d974c840fea7 100644
--- a/subsys/ieee802154/nrf_802154_configurator.c
+++ b/subsys/ieee802154/nrf_802154_configurator.c
@@ -40,9 +40,8 @@ static void ccaed_threshold_configure(void)
 	nrf_802154_cca_cfg_set(&cca_cfg);
 }
 
-static int nrf_802154_configure(const struct device *dev)
+static int nrf_802154_configure(void)
 {
-	ARG_UNUSED(dev);
 
 	ccaed_threshold_configure();
 
diff --git a/subsys/mpsl/cx/bluetooth/mpsl_cx_1w_bluetooth.c b/subsys/mpsl/cx/bluetooth/mpsl_cx_1w_bluetooth.c
index 9b9713337db2..86b586365ca7 100644
--- a/subsys/mpsl/cx/bluetooth/mpsl_cx_1w_bluetooth.c
+++ b/subsys/mpsl/cx/bluetooth/mpsl_cx_1w_bluetooth.c
@@ -88,9 +88,8 @@ static int mpsl_cx_bt_interface_1wire_config_set(void)
 	return err;
 }
 
-static int mpsl_cx_init(const struct device *dev)
+static int mpsl_cx_init(void)
 {
-	ARG_UNUSED(dev);
 
 	return mpsl_cx_bt_interface_1wire_config_set();
 }
diff --git a/subsys/mpsl/cx/nrf700x/mpsl_cx_nrf700x.c b/subsys/mpsl/cx/nrf700x/mpsl_cx_nrf700x.c
index 21910d22706a..8b7217c45249 100644
--- a/subsys/mpsl/cx/nrf700x/mpsl_cx_nrf700x.c
+++ b/subsys/mpsl/cx/nrf700x/mpsl_cx_nrf700x.c
@@ -232,7 +232,7 @@ static const mpsl_cx_interface_t m_mpsl_cx_methods = {
 	.p_register_callback   = register_callback,
 };
 
-static int mpsl_cx_init(const struct device *dev)
+static int mpsl_cx_init(void)
 {
 	int32_t ret;
 
@@ -288,7 +288,7 @@ void mpsl_cx_nrf700x_set_enabled(bool enable)
 }
 
 #else // !defined(CONFIG_MPSL_CX_PIN_FORWARDER)
-static int mpsl_cx_init(const struct device *dev)
+static int mpsl_cx_init(void)
 {
 #if DT_NODE_HAS_PROP(CX_NODE, req_gpios)
 	uint8_t req_pin = NRF_DT_GPIOS_TO_PSEL(CX_NODE, req_gpios);
diff --git a/subsys/mpsl/cx/nrf700x/mpsl_cx_nrf700x_rpc.c b/subsys/mpsl/cx/nrf700x/mpsl_cx_nrf700x_rpc.c
index 8d3753d682e1..6210a5d5d67f 100644
--- a/subsys/mpsl/cx/nrf700x/mpsl_cx_nrf700x_rpc.c
+++ b/subsys/mpsl/cx/nrf700x/mpsl_cx_nrf700x_rpc.c
@@ -87,9 +87,8 @@ static void err_handler(const struct nrf_rpc_err_report *report)
 	k_oops();
 }
 
-static int serialization_init(const struct device *dev)
+static int serialization_init(void)
 {
-	ARG_UNUSED(dev);
 
 	return nrf_rpc_init(err_handler);
 }
diff --git a/subsys/mpsl/cx/thread/mpsl_cx_thread.c b/subsys/mpsl/cx/thread/mpsl_cx_thread.c
index 7e4731e36ddf..b6463bfe5ac0 100644
--- a/subsys/mpsl/cx/thread/mpsl_cx_thread.c
+++ b/subsys/mpsl/cx/thread/mpsl_cx_thread.c
@@ -176,9 +176,8 @@ static const mpsl_cx_interface_t m_mpsl_cx_methods = {
 	.p_register_callback   = register_callback,
 };
 
-static int mpsl_cx_init(const struct device *dev)
+static int mpsl_cx_init(void)
 {
-	ARG_UNUSED(dev);
 
 	int32_t ret;
 
@@ -219,7 +218,7 @@ static int mpsl_cx_init(const struct device *dev)
 SYS_INIT(mpsl_cx_init, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE);
 
 #else // !defined(CONFIG_MPSL_CX_PIN_FORWARDER)
-static int mpsl_cx_init(const struct device *dev)
+static int mpsl_cx_init(void)
 {
 #if DT_NODE_HAS_PROP(CX_NODE, req_gpios)
 	uint8_t req_pin = NRF_DT_GPIOS_TO_PSEL(CX_NODE, req_gpios);
diff --git a/subsys/mpsl/fem/api_init/mpsl_fem_api_init.c b/subsys/mpsl/fem/api_init/mpsl_fem_api_init.c
index c1f3e456a3ac..8f858eaf262a 100644
--- a/subsys/mpsl/fem/api_init/mpsl_fem_api_init.c
+++ b/subsys/mpsl/fem/api_init/mpsl_fem_api_init.c
@@ -7,9 +7,8 @@
 #include <mpsl_fem_init.h>
 #include <zephyr/device.h>
 
-static int mpsl_fem_api_init(const struct device *dev)
+static int mpsl_fem_api_init(void)
 {
-	ARG_UNUSED(dev);
 
 	mpsl_fem_init();
 
diff --git a/subsys/mpsl/fem/nrf21540_gpio/mpsl_fem_nrf21540_gpio.c b/subsys/mpsl/fem/nrf21540_gpio/mpsl_fem_nrf21540_gpio.c
index abd4ea52f156..89a23cb897c8 100644
--- a/subsys/mpsl/fem/nrf21540_gpio/mpsl_fem_nrf21540_gpio.c
+++ b/subsys/mpsl/fem/nrf21540_gpio/mpsl_fem_nrf21540_gpio.c
@@ -198,9 +198,8 @@ static int fem_nrf21540_gpio_configure(void)
 	return mpsl_fem_nrf21540_gpio_interface_config_set(&cfg);
 }
 
-static int mpsl_fem_init(const struct device *dev)
+static int mpsl_fem_init(void)
 {
-	ARG_UNUSED(dev);
 
 #if IS_ENABLED(CONFIG_MPSL_FEM_POWER_MODEL)
 	int err;
@@ -222,9 +221,8 @@ SYS_INIT(mpsl_fem_init, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE);
 
 #else /* !defined(CONFIG_MPSL_FEM_PIN_FORWARDER) */
 
-static int mpsl_fem_host_init(const struct device *dev)
+static int mpsl_fem_host_init(void)
 {
-	ARG_UNUSED(dev);
 
 #if DT_NODE_HAS_PROP(DT_NODELABEL(nrf_radio_fem), tx_en_gpios)
 	uint8_t tx_en_pin = NRF_DT_GPIOS_TO_PSEL(DT_NODELABEL(nrf_radio_fem), tx_en_gpios);
diff --git a/subsys/mpsl/fem/nrf21540_gpio_spi/models/mpsl_fem_nrf21540_power_model_builtin.c b/subsys/mpsl/fem/nrf21540_gpio_spi/models/mpsl_fem_nrf21540_power_model_builtin.c
index df0b8c6e5f57..552896da1fde 100644
--- a/subsys/mpsl/fem/nrf21540_gpio_spi/models/mpsl_fem_nrf21540_power_model_builtin.c
+++ b/subsys/mpsl/fem/nrf21540_gpio_spi/models/mpsl_fem_nrf21540_power_model_builtin.c
@@ -43,7 +43,7 @@ static void model_update_timeout(struct k_timer *dummy)
 
 K_TIMER_DEFINE(model_update_timer, model_update_timeout, NULL);
 
-static int model_periodic_update_start(const struct device *unused)
+static int model_periodic_update_start(void)
 {
 	/* Perform initial model update */
 	k_work_submit(&model_update_work);
diff --git a/subsys/mpsl/fem/nrf21540_gpio_spi/mpsl_fem_nrf21540_gpio_spi.c b/subsys/mpsl/fem/nrf21540_gpio_spi/mpsl_fem_nrf21540_gpio_spi.c
index d77dd94c73e7..936bc9edacd9 100644
--- a/subsys/mpsl/fem/nrf21540_gpio_spi/mpsl_fem_nrf21540_gpio_spi.c
+++ b/subsys/mpsl/fem/nrf21540_gpio_spi/mpsl_fem_nrf21540_gpio_spi.c
@@ -306,9 +306,8 @@ static int fem_nrf21540_gpio_spi_configure(void)
 	return err;
 }
 
-static int mpsl_fem_init(const struct device *dev)
+static int mpsl_fem_init(void)
 {
-	ARG_UNUSED(dev);
 
 	mpsl_fem_device_config_254_apply_set(IS_ENABLED(CONFIG_MPSL_FEM_DEVICE_CONFIG_254));
 
diff --git a/subsys/mpsl/fem/simple_gpio/mpsl_fem_simple_gpio.c b/subsys/mpsl/fem/simple_gpio/mpsl_fem_simple_gpio.c
index 8344aff17b71..184497e8f727 100644
--- a/subsys/mpsl/fem/simple_gpio/mpsl_fem_simple_gpio.c
+++ b/subsys/mpsl/fem/simple_gpio/mpsl_fem_simple_gpio.c
@@ -116,9 +116,8 @@ static int fem_simple_gpio_configure(void)
 	return mpsl_fem_simple_gpio_interface_config_set(&cfg);
 }
 
-static int mpsl_fem_init(const struct device *dev)
+static int mpsl_fem_init(void)
 {
-	ARG_UNUSED(dev);
 
 #if IS_ENABLED(CONFIG_MPSL_FEM_POWER_MODEL)
 	int err;
@@ -140,9 +139,8 @@ SYS_INIT(mpsl_fem_init, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE);
 
 #else /* !defined(CONFIG_MPSL_FEM_PIN_FORWARDER) */
 
-static int mpsl_fem_host_init(const struct device *dev)
+static int mpsl_fem_host_init(void)
 {
-	ARG_UNUSED(dev);
 
 #if DT_NODE_HAS_PROP(DT_NODELABEL(nrf_radio_fem), ctx_gpios)
 	uint8_t ctx_pin = NRF_DT_GPIOS_TO_PSEL(DT_NODELABEL(nrf_radio_fem), ctx_gpios);
diff --git a/subsys/mpsl/init/mpsl_init.c b/subsys/mpsl/init/mpsl_init.c
index 7562958fc40e..8f958d825964 100644
--- a/subsys/mpsl/init/mpsl_init.c
+++ b/subsys/mpsl/init/mpsl_init.c
@@ -235,9 +235,8 @@ static int32_t mpsl_lib_init_internal(void)
 	return 0;
 }
 
-static int mpsl_lib_init_sys(const struct device *dev)
+static int mpsl_lib_init_sys(void)
 {
-	ARG_UNUSED(dev);
 	int err = 0;
 
 	err = mpsl_lib_init_internal();
@@ -275,9 +274,8 @@ static int mpsl_lib_init_sys(const struct device *dev)
 	return 0;
 }
 
-static int mpsl_low_prio_init(const struct device *dev)
+static int mpsl_low_prio_init(void)
 {
-	ARG_UNUSED(dev);
 
 	k_work_queue_start(&mpsl_work_q, mpsl_work_stack,
 			   K_THREAD_STACK_SIZEOF(mpsl_work_stack),
diff --git a/subsys/net/lib/download_client/src/shell.c b/subsys/net/lib/download_client/src/shell.c
index 55e096f2a8db..645812e86a2c 100644
--- a/subsys/net/lib/download_client/src/shell.c
+++ b/subsys/net/lib/download_client/src/shell.c
@@ -57,7 +57,7 @@ static int callback(const struct download_client_evt *event)
 	return 0;
 }
 
-static int download_shell_init(const struct device *d)
+static int download_shell_init(void)
 {
 	return download_client_init(&downloader, callback);
 }
diff --git a/subsys/net/lib/lwm2m_client_utils/location/location_assistance.c b/subsys/net/lib/lwm2m_client_utils/location/location_assistance.c
index b8db66164908..ce806f85b86c 100644
--- a/subsys/net/lib/lwm2m_client_utils/location/location_assistance.c
+++ b/subsys/net/lib/lwm2m_client_utils/location/location_assistance.c
@@ -222,7 +222,7 @@ static int do_agps_request_send(struct lwm2m_ctx *ctx, bool confirmable)
 	};
 
 	/* Send Request to server */
-	return lwm2m_send(ctx, send_path, path_count, confirmable);
+	return lwm2m_send_cb(ctx, send_path, path_count, NULL);
 }
 
 #if defined(CONFIG_LWM2M_CLIENT_UTILS_LOCATION_ASSIST_AGPS)
@@ -273,7 +273,7 @@ static int do_ground_fix_request_send(struct lwm2m_ctx *ctx, bool confirmable)
 	};
 
 	/* Send Request to server */
-	return lwm2m_send(ctx, send_path, path_count, confirmable);
+	return lwm2m_send_cb(ctx, send_path, path_count, NULL);
 }
 
 #if defined(CONFIG_LWM2M_CLIENT_UTILS_GROUND_FIX_OBJ_SUPPORT)
@@ -312,7 +312,7 @@ static int do_pgps_request_send(struct lwm2m_ctx *ctx, bool confirmable)
 	};
 
 	/* Send Request to server */
-	return lwm2m_send(ctx, send_path, path_count, confirmable);
+	return lwm2m_send_cb(ctx, send_path, path_count, NULL);
 }
 
 #if defined(CONFIG_LWM2M_CLIENT_UTILS_LOCATION_ASSIST_PGPS)
diff --git a/subsys/net/lib/lwm2m_client_utils/location/location_wifi_ap_scanner.c b/subsys/net/lib/lwm2m_client_utils/location/location_wifi_ap_scanner.c
index 402a2a08ebdb..c750701d3a71 100644
--- a/subsys/net/lib/lwm2m_client_utils/location/location_wifi_ap_scanner.c
+++ b/subsys/net/lib/lwm2m_client_utils/location/location_wifi_ap_scanner.c
@@ -111,7 +111,7 @@ int lwm2m_wifi_request_scan(void)
 	return ret;
 }
 
-static int lwm2m_wifi_scan_init(const struct device *dev)
+static int lwm2m_wifi_scan_init(void)
 {
 	const struct device *wifi_dev;
 
diff --git a/subsys/net/lib/lwm2m_client_utils/lwm2m/ecid_signal_meas_info.c b/subsys/net/lib/lwm2m_client_utils/lwm2m/ecid_signal_meas_info.c
index 30aafec0069e..0fc3034ba84e 100644
--- a/subsys/net/lib/lwm2m_client_utils/lwm2m/ecid_signal_meas_info.c
+++ b/subsys/net/lib/lwm2m_client_utils/lwm2m/ecid_signal_meas_info.c
@@ -204,7 +204,7 @@ static struct lwm2m_engine_obj_inst *signal_meas_info_create(uint16_t obj_inst_i
 	return &inst[index];
 }
 
-static int lwm2m_signal_meas_info_init(const struct device *dev)
+static int lwm2m_signal_meas_info_init(void)
 {
 	int ret = 0;
 
diff --git a/subsys/net/lib/lwm2m_client_utils/lwm2m/gnss_assistance_obj.c b/subsys/net/lib/lwm2m_client_utils/lwm2m/gnss_assistance_obj.c
index 961032fe4585..f6072ad50973 100644
--- a/subsys/net/lib/lwm2m_client_utils/lwm2m/gnss_assistance_obj.c
+++ b/subsys/net/lib/lwm2m_client_utils/lwm2m/gnss_assistance_obj.c
@@ -363,7 +363,7 @@ static struct lwm2m_engine_obj_inst *gnss_assist_create(uint16_t obj_inst_id)
 	return &inst;
 }
 
-static int lwm2m_gnss_assist_init(const struct device *dev)
+static int lwm2m_gnss_assist_init(void)
 {
 	struct lwm2m_engine_obj_inst *obj_inst = NULL;
 	int ret = 0;
diff --git a/subsys/net/lib/lwm2m_client_utils/lwm2m/ground_fix_obj.c b/subsys/net/lib/lwm2m_client_utils/lwm2m/ground_fix_obj.c
index 5d374d3ce915..1fc4b7da6502 100644
--- a/subsys/net/lib/lwm2m_client_utils/lwm2m/ground_fix_obj.c
+++ b/subsys/net/lib/lwm2m_client_utils/lwm2m/ground_fix_obj.c
@@ -102,7 +102,7 @@ static struct lwm2m_engine_obj_inst *ground_fix_create(uint16_t obj_inst_id)
 	return &inst;
 }
 
-static int lwm2m_ground_fix_init(const struct device *dev)
+static int lwm2m_ground_fix_init(void)
 {
 	struct lwm2m_engine_obj_inst *obj_inst = NULL;
 	int ret = 0;
diff --git a/subsys/net/lib/lwm2m_client_utils/lwm2m/lwm2m_adv_firmware.c b/subsys/net/lib/lwm2m_client_utils/lwm2m/lwm2m_adv_firmware.c
index 6f0d0bc65ce9..5dab85cce7de 100644
--- a/subsys/net/lib/lwm2m_client_utils/lwm2m/lwm2m_adv_firmware.c
+++ b/subsys/net/lib/lwm2m_client_utils/lwm2m/lwm2m_adv_firmware.c
@@ -559,7 +559,7 @@ int lwm2m_adv_firmware_create_inst(const char *component, lwm2m_engine_set_data_
 	return ret;
 }
 
-static int lwm2m_adv_firmware_init(const struct device *dev)
+static int lwm2m_adv_firmware_init(void)
 {
 	/* Set default values */
 	firmware.obj_id = LWM2M_OBJECT_ADV_FIRMWARE_ID;
diff --git a/subsys/net/lib/lwm2m_client_utils/lwm2m/lwm2m_cellconn_obj.c b/subsys/net/lib/lwm2m_client_utils/lwm2m/lwm2m_cellconn_obj.c
index 70e40cc37b3c..8563012138d7 100644
--- a/subsys/net/lib/lwm2m_client_utils/lwm2m/lwm2m_cellconn_obj.c
+++ b/subsys/net/lib/lwm2m_client_utils/lwm2m/lwm2m_cellconn_obj.c
@@ -150,7 +150,7 @@ static struct lwm2m_engine_obj_inst *cellconn_create(uint16_t obj_inst_id)
 	return &inst;
 }
 
-static int lwm2m_cellconn_init(const struct device *dev)
+static int lwm2m_cellconn_init(void)
 {
 	cellconn.obj_id = LWM2M_OBJECT_CELLULAR_CONNECTIVITY_ID;
 	cellconn.version_major = CELLCONN_VERSION_MAJOR;
diff --git a/subsys/net/lib/lwm2m_client_utils/lwm2m/lwm2m_connmon.c b/subsys/net/lib/lwm2m_client_utils/lwm2m/lwm2m_connmon.c
index f63f2dd2caf7..2b8433589bb9 100644
--- a/subsys/net/lib/lwm2m_client_utils/lwm2m/lwm2m_connmon.c
+++ b/subsys/net/lib/lwm2m_client_utils/lwm2m/lwm2m_connmon.c
@@ -194,7 +194,7 @@ static void connmon_lte_notify_handler(const struct lte_lc_evt *const evt)
 	}
 }
 
-int lwm2m_init_connmon(const struct device *dev)
+int lwm2m_init_connmon(void)
 {
 	int ret;
 
diff --git a/subsys/net/lib/lwm2m_client_utils/lwm2m/visible_wifi_ap.c b/subsys/net/lib/lwm2m_client_utils/lwm2m/visible_wifi_ap.c
index bf6ba093234c..5b676e133e07 100644
--- a/subsys/net/lib/lwm2m_client_utils/lwm2m/visible_wifi_ap.c
+++ b/subsys/net/lib/lwm2m_client_utils/lwm2m/visible_wifi_ap.c
@@ -106,7 +106,7 @@ static struct lwm2m_engine_obj_inst *visible_wifi_ap_create(uint16_t obj_inst_id
 	return &inst[index];
 }
 
-static int lwm2m_visible_wifi_ap_init(const struct device *dev)
+static int lwm2m_visible_wifi_ap_init(void)
 {
 	int ret = 0;
 
diff --git a/subsys/net/lib/wifi_credentials/wifi_credentials.c b/subsys/net/lib/wifi_credentials/wifi_credentials.c
index cfdf48ccb50b..2d97621f6911 100644
--- a/subsys/net/lib/wifi_credentials/wifi_credentials.c
+++ b/subsys/net/lib/wifi_credentials/wifi_credentials.c
@@ -67,9 +67,8 @@ static inline ssize_t lookup_unused_idx(void)
 	return -1;
 }
 
-static int init(const struct device *dev)
+static int init(void)
 {
-	ARG_UNUSED(dev);
 
 	int ret;
 
diff --git a/subsys/nfc/t4t/isodep.c b/subsys/nfc/t4t/isodep.c
index 9fed3c776080..fd616ed04ff0 100644
--- a/subsys/nfc/t4t/isodep.c
+++ b/subsys/nfc/t4t/isodep.c
@@ -52,7 +52,7 @@ LOG_MODULE_REGISTER(nfc_t4t_isodep, CONFIG_NFC_T4T_ISODEP_LOG_LEVEL);
 #define T4T_FC_IN_MS 13560UL
 
 #define T4T_FWT_TO_MS(_fwt)                   \
-	ceiling_fraction((_fwt), T4T_FC_IN_MS)
+	DIV_ROUND_UP((_fwt), T4T_FC_IN_MS)
 
 #define T4T_RATS_FDT (T4T_FWT_ACTIVATION +        \
 		T4T_FWT_DELTA + NFCA_T4T_FWT_T_FC)
diff --git a/subsys/nfc/tnep/poller.c b/subsys/nfc/tnep/poller.c
index a48b7ae18fbb..73566bf1d517 100644
--- a/subsys/nfc/tnep/poller.c
+++ b/subsys/nfc/tnep/poller.c
@@ -29,7 +29,7 @@ LOG_MODULE_REGISTER(nfc_tnep_poller, CONFIG_NFC_TNEP_POLLER_LOG_LEVEL);
  * Exchange Protocol 1.0 4.1.6
  */
 #define NFC_TNEP_MIN_WAIT_TIME(_time) \
-	(1 << (((ceiling_fraction((_time), 4)) - 1)))
+	(1 << (((DIV_ROUND_UP((_time), 4)) - 1)))
 
 enum tnep_poller_state {
 	TNEP_POLLER_STATE_IDLE,
diff --git a/subsys/shell/shell_ipc.c b/subsys/shell/shell_ipc.c
index e9ab5cc05182..f991f3059cde 100644
--- a/subsys/shell/shell_ipc.c
+++ b/subsys/shell/shell_ipc.c
@@ -170,9 +170,8 @@ static const struct shell_transport_api shell_ipc_transport_api = {
 	.read = read,
 };
 
-static int enable_shell_ipc(const struct device *arg)
+static int enable_shell_ipc(void)
 {
-	ARG_UNUSED(arg);
 
 	const struct device *dev = DEVICE_DT_GET(DT_CHOSEN(zephyr_shell_ipc));
 	bool log_backend = CONFIG_SHELL_IPC_INIT_LOG_LEVEL > 0;
diff --git a/subsys/zigbee/Kconfig b/subsys/zigbee/Kconfig
index 9642d36c0068..11f2dee79a8e 100644
--- a/subsys/zigbee/Kconfig
+++ b/subsys/zigbee/Kconfig
@@ -360,15 +360,18 @@ config ZIGBEE_TC_REJOIN_ENABLED
 	bool "Enables Trust Center Rejoin"
 	default y
 
+DT_CHOSEN_NCS_ZIGBEE_TIMER := ncs,zigbee-timer
+
 choice
 	prompt "ZBOSS time source"
-	default ZIGBEE_TIME_COUNTER if ZIGBEE_LIBRARY_PRODUCTION
+	default ZIGBEE_TIME_COUNTER if ZIGBEE_LIBRARY_PRODUCTION && \
+		$(dt_chosen_enabled,$(DT_CHOSEN_NCS_ZIGBEE_TIMER))
 	default ZIGBEE_TIME_KTIMER if ZIGBEE_LIBRARY_DEVELOPMENT
 
 config ZIGBEE_TIME_COUNTER
 	bool "Dedicated timer-based counter"
+	depends on $(dt_chosen_enabled,$(DT_CHOSEN_NCS_ZIGBEE_TIMER))
 	imply COUNTER
-	imply COUNTER_TIMER2
 
 config ZIGBEE_TIME_KTIMER
 	bool "Kernel (system) time"
diff --git a/subsys/zigbee/osif/zb_nrf_pwr_mgmt.c b/subsys/zigbee/osif/zb_nrf_pwr_mgmt.c
index a8a6dee6123f..79dd038d1c5e 100644
--- a/subsys/zigbee/osif/zb_nrf_pwr_mgmt.c
+++ b/subsys/zigbee/osif/zb_nrf_pwr_mgmt.c
@@ -24,10 +24,10 @@ void zb_timer_enable_stop(void);
  */
 void zb_osif_sleep_init(void)
 {
-#ifdef CONFIG_COUNTER_TIMER2
 	/* Disable timer in inactivity periods on all device types. */
-	zb_timer_enable_stop();
-#endif /* CONFIG_COUNTER_TIMER2 */
+	if (IS_ENABLED(CONFIG_ZIGBEE_TIME_COUNTER)) {
+		zb_timer_enable_stop();
+	}
 }
 
 /**@brief Function which tries to put the MMCU into sleep mode,
@@ -74,7 +74,7 @@ __weak zb_uint32_t zb_osif_sleep(zb_uint32_t sleep_tmo)
 	 * in the time unit conversion.
 	 */
 	time_slept_ms = ZB_TIME_BEACON_INTERVAL_TO_MSEC(
-		ceiling_fraction(time_slept_us, ZB_BEACON_INTERVAL_USEC));
+		DIV_ROUND_UP(time_slept_us, ZB_BEACON_INTERVAL_USEC));
 
 	/* Unlock timer value updates. */
 	ZVUNUSED(atomic_set((atomic_t *)&is_sleeping, 0));
diff --git a/subsys/zigbee/osif/zb_nrf_timer_counter.c b/subsys/zigbee/osif/zb_nrf_timer_counter.c
index 10c398c22608..59ee957b20c1 100644
--- a/subsys/zigbee/osif/zb_nrf_timer_counter.c
+++ b/subsys/zigbee/osif/zb_nrf_timer_counter.c
@@ -27,7 +27,7 @@ typedef struct {
 } zb_timer_t;
 
 static zb_timer_t zb_timer = {
-	.device = DEVICE_DT_GET(DT_NODELABEL(timer2)),
+	.device = DEVICE_DT_GET(DT_CHOSEN(ncs_zigbee_timer)),
 	.is_init = ZB_FALSE,
 	.is_running = ATOMIC_INIT(0)
 };
diff --git a/tests/bluetooth/tester/src/main.c b/tests/bluetooth/tester/src/main.c
index 2bd20e946bc0..ae4ed1cb87df 100644
--- a/tests/bluetooth/tester/src/main.c
+++ b/tests/bluetooth/tester/src/main.c
@@ -16,7 +16,9 @@ LOG_MODULE_REGISTER(LOG_MODULE_NAME);
 
 #include "bttester.h"
 
-void main(void)
+int main(void)
 {
 	tester_init();
+
+	return 0;
 }
diff --git a/tests/drivers/lpuart/boards/nrf9160dk_nrf52840.conf b/tests/drivers/lpuart/boards/nrf9160dk_nrf52840.conf
index e0071253378a..687809f706b0 100644
--- a/tests/drivers/lpuart/boards/nrf9160dk_nrf52840.conf
+++ b/tests/drivers/lpuart/boards/nrf9160dk_nrf52840.conf
@@ -5,7 +5,5 @@ CONFIG_UART_1_NRF_ASYNC_LOW_POWER=y
 CONFIG_UART_1_NRF_HW_ASYNC_TIMER=2
 CONFIG_NRF_SW_LPUART=y
 
-CONFIG_COUNTER_TIMER3=y
-CONFIG_NRFX_TIMER3=y
 CONFIG_COUNTER=y
 CONFIG_ENTROPY_CC3XX=y
diff --git a/tests/drivers/lpuart/boards/nrf9160dk_nrf52840.overlay b/tests/drivers/lpuart/boards/nrf9160dk_nrf52840.overlay
index 1fcfe65b83de..43675e10c83b 100644
--- a/tests/drivers/lpuart/boards/nrf9160dk_nrf52840.overlay
+++ b/tests/drivers/lpuart/boards/nrf9160dk_nrf52840.overlay
@@ -49,7 +49,7 @@
 };
 
 &timer3 {
-	status = "ok";
+	status = "okay";
 	interrupts = <26 0>;
 };
 
diff --git a/tests/drivers/lpuart/boards/nrf9160dk_nrf9160.conf b/tests/drivers/lpuart/boards/nrf9160dk_nrf9160.conf
index 8d806b756ca3..c03142840b2d 100644
--- a/tests/drivers/lpuart/boards/nrf9160dk_nrf9160.conf
+++ b/tests/drivers/lpuart/boards/nrf9160dk_nrf9160.conf
@@ -6,6 +6,5 @@ CONFIG_UART_2_NRF_HW_ASYNC=y
 CONFIG_UART_2_NRF_ASYNC_LOW_POWER=y
 CONFIG_UART_2_NRF_HW_ASYNC_TIMER=2
 
-CONFIG_COUNTER_TIMER0=y
 CONFIG_COUNTER=y
 CONFIG_ENTROPY_CC3XX=y
diff --git a/tests/drivers/lpuart/boards/nrf9160dk_nrf9160.overlay b/tests/drivers/lpuart/boards/nrf9160dk_nrf9160.overlay
index a8fb0f723827..458063400df4 100644
--- a/tests/drivers/lpuart/boards/nrf9160dk_nrf9160.overlay
+++ b/tests/drivers/lpuart/boards/nrf9160dk_nrf9160.overlay
@@ -44,6 +44,7 @@
 };
 
 &timer0 {
+	status = "okay";
 	interrupts = <15 0>;
 };
 
diff --git a/tests/drivers/lpuart/boards/nrf9160dk_nrf9160_loopback.overlay b/tests/drivers/lpuart/boards/nrf9160dk_nrf9160_loopback.overlay
index bc4261a4dfc2..d6260ff97a95 100644
--- a/tests/drivers/lpuart/boards/nrf9160dk_nrf9160_loopback.overlay
+++ b/tests/drivers/lpuart/boards/nrf9160dk_nrf9160_loopback.overlay
@@ -44,6 +44,7 @@
 };
 
 &timer0 {
+	status = "okay";
 	interrupts = <15 0>;
 };
 
diff --git a/tests/lib/hw_id/src/main.c b/tests/lib/hw_id/src/main.c
index 9dc77801498d..b07a0a9775d7 100644
--- a/tests/lib/hw_id/src/main.c
+++ b/tests/lib/hw_id/src/main.c
@@ -125,10 +125,16 @@ void test_too_small(void)
 	TEST_ASSERT_EQUAL(0, strcmp("", buf));
 }
 
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
+ */
 extern int unity_main(void);
 
-void main(void)
+int main(void)
 {
 	/* use the runner from test_runner_generate() */
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/tests/lib/location/src/location_test.c b/tests/lib/location/src/location_test.c
index d952ab148281..0156cceb7b9d 100644
--- a/tests/lib/location/src/location_test.c
+++ b/tests/lib/location/src/location_test.c
@@ -943,22 +943,24 @@ void test_location_cellular_periodic(void)
 }
 
 /* This is needed because AT Monitor library is initialized in SYS_INIT. */
-static int location_test_sys_init(const struct device *unused)
+static int location_test_sys_init(void)
 {
 	__cmock_nrf_modem_at_notif_handler_set_ExpectAnyArgsAndReturn(0);
 
 	return 0;
 }
 
-/* It is required to be added to each test. That is because unity is using
- * different main signature (returns int) and zephyr expects main which does
- * not return value.
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
  */
 extern int unity_main(void);
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+
+	return 0;
 }
 
 SYS_INIT(location_test_sys_init, POST_KERNEL, 0);
diff --git a/tests/lib/lte_lc_api/src/lte_lc_api_test.c b/tests/lib/lte_lc_api/src/lte_lc_api_test.c
index 168a7de32e60..3e577f5778de 100644
--- a/tests/lib/lte_lc_api/src/lte_lc_api_test.c
+++ b/tests/lib/lte_lc_api/src/lte_lc_api_test.c
@@ -50,7 +50,7 @@ void tearDown(void)
 }
 
 /* This is needed because AT Monitor library is initialized in SYS_INIT. */
-static int sys_init_helper(const struct device *unused)
+static int sys_init_helper(void)
 {
 	__cmock_nrf_modem_at_notif_handler_set_ExpectAnyArgsAndReturn(0);
 
@@ -1046,15 +1046,17 @@ void test_lte_lc_periodic_search_get_success(void)
 	TEST_ASSERT_EQUAL(EXIT_SUCCESS, ret);
 }
 
-/* It is required to be added to each test. That is because unity is using
- * different main signature (returns int) and zephyr expects main which does
- * not return value.
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
  */
 extern int unity_main(void);
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+
+	return 0;
 }
 
 SYS_INIT(sys_init_helper, POST_KERNEL, 0);
diff --git a/tests/lib/modem_info/src/main.c b/tests/lib/modem_info/src/main.c
index 8b60bd95baae..801290529892 100644
--- a/tests/lib/modem_info/src/main.c
+++ b/tests/lib/modem_info/src/main.c
@@ -406,9 +406,15 @@ void test_modem_info_get_rsrp_success(void)
 	TEST_ASSERT_EQUAL(1, nrf_modem_at_scanf_fake.call_count);
 }
 
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
+ */
 extern int unity_main(void);
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/tests/lib/modem_jwt/src/jwt_test.c b/tests/lib/modem_jwt/src/jwt_test.c
index b763bb091835..f7890106fa44 100644
--- a/tests/lib/modem_jwt/src/jwt_test.c
+++ b/tests/lib/modem_jwt/src/jwt_test.c
@@ -107,9 +107,15 @@ void test_modem_jwt_get_uuids(void)
 	TEST_ASSERT_EQUAL_STRING("f72d9789-2e73-4780-9248-b3952f89b872", mfw.str);
 }
 
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
+ */
 extern int unity_main(void);
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/tests/lib/nrf_modem_lib/nrf91_sockets/src/nrf91_sockets_test.c b/tests/lib/nrf_modem_lib/nrf91_sockets/src/nrf91_sockets_test.c
index 5d1edcf83dd3..392cfbbe8ceb 100644
--- a/tests/lib/nrf_modem_lib/nrf91_sockets/src/nrf91_sockets_test.c
+++ b/tests/lib/nrf_modem_lib/nrf91_sockets/src/nrf91_sockets_test.c
@@ -1788,13 +1788,15 @@ void test_nrf91_socket_offload_poll(void)
 	TEST_ASSERT_EQUAL(ret, 0);
 }
 
-/* It is required to be added to each test. That is because unity is using
- * different main signature (returns int) and zephyr expects main which does
- * not return value.
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
  */
 extern int unity_main(void);
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/tests/lib/nrf_modem_lib/nrf_modem_lib_trace/src/main.c b/tests/lib/nrf_modem_lib/nrf_modem_lib_trace/src/main.c
index 81cf04cff41c..99394c6586ee 100644
--- a/tests/lib/nrf_modem_lib/nrf_modem_lib_trace/src/main.c
+++ b/tests/lib/nrf_modem_lib/nrf_modem_lib_trace/src/main.c
@@ -21,6 +21,10 @@
 
 LOG_MODULE_REGISTER(trace_test, CONFIG_NRF_MODEM_LIB_TRACE_TEST_LOG_LEVEL);
 
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
+ */
 extern int unity_main(void);
 
 extern struct nrf_modem_lib_trace_backend trace_backend;
@@ -467,7 +471,9 @@ void test_nrf_modem_lib_trace_enotsup(void)
 	trace_backend = trace_backend_orig;
 }
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/tests/lib/nrf_modem_lib/trace_backends/rtt/src/main.c b/tests/lib/nrf_modem_lib/trace_backends/rtt/src/main.c
index 38ff1e28cf4c..4a32e78a7ad2 100644
--- a/tests/lib/nrf_modem_lib/trace_backends/rtt/src/main.c
+++ b/tests/lib/nrf_modem_lib/trace_backends/rtt/src/main.c
@@ -21,6 +21,10 @@ static int callback(size_t len)
 	return 0;
 }
 
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
+ */
 extern int unity_main(void);
 
 static int trace_rtt_channel;
@@ -94,7 +98,9 @@ void test_trace_backend_write_rtt(void)
 	trace_backend.write(sample_trace_data, sizeof(sample_trace_data));
 }
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/tests/lib/nrf_modem_lib/trace_backends/uart/src/main.c b/tests/lib/nrf_modem_lib/trace_backends/uart/src/main.c
index 78ba5380d963..6a89b9c311c4 100644
--- a/tests/lib/nrf_modem_lib/trace_backends/uart/src/main.c
+++ b/tests/lib/nrf_modem_lib/trace_backends/uart/src/main.c
@@ -14,6 +14,10 @@
 #include "cmock_nrfx_uarte.h"
 #include "cmock_pinctrl.h"
 
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
+ */
 extern int unity_main(void);
 
 extern struct nrf_modem_lib_trace_backend trace_backend;
@@ -290,7 +294,9 @@ void test_trace_backend_write_uart_nrfx_uarte_evt_error(void)
 	TEST_ASSERT_EQUAL(true, is_waiting_on_traces);
 }
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/tests/lib/qos/src/qos_test.c b/tests/lib/qos/src/qos_test.c
index f283d9eb0a06..9d051f30459b 100644
--- a/tests/lib/qos/src/qos_test.c
+++ b/tests/lib/qos/src/qos_test.c
@@ -338,9 +338,15 @@ void test_message_timeout_work(void)
 	TEST_ASSERT_EQUAL(0, callback_count);
 }
 
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
+ */
 extern int unity_main(void);
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/tests/lib/sms/src/sms_test.c b/tests/lib/sms/src/sms_test.c
index 51a533b0468f..09acb985484f 100644
--- a/tests/lib/sms/src/sms_test.c
+++ b/tests/lib/sms/src/sms_test.c
@@ -1774,22 +1774,24 @@ void test_recv_loop(void)
 }
 
 /* This is needed because AT Monitor library is initialized in SYS_INIT. */
-static int sms_test_sys_init(const struct device *unused)
+static int sms_test_sys_init(void)
 {
 	__cmock_nrf_modem_at_notif_handler_set_ExpectAnyArgsAndReturn(0);
 
 	return 0;
 }
 
-/* It is required to be added to each test. That is because unity is using
- * different main signature (returns int) and zephyr expects main which does
- * not return value.
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
  */
 extern int unity_main(void);
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+
+	return 0;
 }
 
 SYS_INIT(sms_test_sys_init, POST_KERNEL, 0);
diff --git a/tests/subsys/bluetooth/fast_pair/storage/account_key_storage/src/settings_mock.c b/tests/subsys/bluetooth/fast_pair/storage/account_key_storage/src/settings_mock.c
index 972fa787a143..f0d49f069331 100644
--- a/tests/subsys/bluetooth/fast_pair/storage/account_key_storage/src/settings_mock.c
+++ b/tests/subsys/bluetooth/fast_pair/storage/account_key_storage/src/settings_mock.c
@@ -143,9 +143,8 @@ static struct settings_store settings_mock_store = {
 	.cs_itf = &settings_mock_itf
 };
 
-int settings_mock_init(const struct device *unused)
+int settings_mock_init(void)
 {
-	ARG_UNUSED(unused);
 	sys_slist_init(&settings_list);
 
 	settings_dst_register(&settings_mock_store);
diff --git a/tests/subsys/bluetooth/mesh/light_ctrl/CMakeLists.txt b/tests/subsys/bluetooth/mesh/light_ctrl/CMakeLists.txt
index 85d0b960791f..0a0cede0db9d 100644
--- a/tests/subsys/bluetooth/mesh/light_ctrl/CMakeLists.txt
+++ b/tests/subsys/bluetooth/mesh/light_ctrl/CMakeLists.txt
@@ -18,7 +18,6 @@ target_sources(app
   ${NRF_DIR}/subsys/bluetooth/mesh/light_ctrl_reg_spec.c
   ${NRF_DIR}/subsys/bluetooth/mesh/sensor_types.c
   ${NRF_DIR}/subsys/bluetooth/mesh/sensor.c
-  ${ZEPHYR_BASE}/subsys/net/buf.c
   )
 
 target_include_directories(app
diff --git a/tests/subsys/bluetooth/mesh/light_ctrl/prj.conf b/tests/subsys/bluetooth/mesh/light_ctrl/prj.conf
index 026cb41ca467..cb7e4bce6fd8 100644
--- a/tests/subsys/bluetooth/mesh/light_ctrl/prj.conf
+++ b/tests/subsys/bluetooth/mesh/light_ctrl/prj.conf
@@ -9,3 +9,5 @@ CONFIG_ZTEST=y
 CONFIG_ZTEST_NEW_API=y
 CONFIG_ZTEST_MOCKING=y
 CONFIG_ZTEST_PARAMETER_COUNT=30
+
+CONFIG_NET_BUF=y
diff --git a/tests/subsys/bluetooth/mesh/models/src/main.c b/tests/subsys/bluetooth/mesh/models/src/main.c
index 47b1b56e8fbf..5b20b68cc479 100644
--- a/tests/subsys/bluetooth/mesh/models/src/main.c
+++ b/tests/subsys/bluetooth/mesh/models/src/main.c
@@ -113,7 +113,9 @@ static const struct bt_mesh_comp comp = {
 	.elem_count = ARRAY_SIZE(elems),
 };
 
-void main(void)
+int main(void)
 {
 	bt_mesh_init(NULL, &comp);
+
+	return 0;
 }
diff --git a/tests/subsys/bluetooth/mesh/scheduler_model/action_planning/CMakeLists.txt b/tests/subsys/bluetooth/mesh/scheduler_model/action_planning/CMakeLists.txt
index ab2012d3ec71..0f1fa620ab03 100644
--- a/tests/subsys/bluetooth/mesh/scheduler_model/action_planning/CMakeLists.txt
+++ b/tests/subsys/bluetooth/mesh/scheduler_model/action_planning/CMakeLists.txt
@@ -21,7 +21,6 @@ target_sources(app PRIVATE
   ${NRF_DIR}/subsys/bluetooth/mesh/scheduler_srv.c
   ${NRF_DIR}/subsys/bluetooth/mesh/time_util.c
   ${NRF_DIR}/subsys/bluetooth/mesh/model_utils.c
-  ${ZEPHYR_BASE}/subsys/net/buf.c
   ../common/sched_test.c
   )
 
diff --git a/tests/subsys/bluetooth/mesh/scheduler_model/action_planning/prj.conf b/tests/subsys/bluetooth/mesh/scheduler_model/action_planning/prj.conf
index 6f59d9ff0d1d..f43b47f76dbc 100644
--- a/tests/subsys/bluetooth/mesh/scheduler_model/action_planning/prj.conf
+++ b/tests/subsys/bluetooth/mesh/scheduler_model/action_planning/prj.conf
@@ -8,3 +8,5 @@
 CONFIG_ZTEST=y
 CONFIG_ZTEST_NEW_API=y
 CONFIG_TEST_RANDOM_GENERATOR=y
+
+CONFIG_NET_BUF=y
diff --git a/tests/subsys/bluetooth/mesh/scheduler_model/message_validity/CMakeLists.txt b/tests/subsys/bluetooth/mesh/scheduler_model/message_validity/CMakeLists.txt
index 747f3300ce62..6894559b2e93 100644
--- a/tests/subsys/bluetooth/mesh/scheduler_model/message_validity/CMakeLists.txt
+++ b/tests/subsys/bluetooth/mesh/scheduler_model/message_validity/CMakeLists.txt
@@ -22,7 +22,6 @@ target_sources(app PRIVATE
   ${NRF_DIR}/subsys/bluetooth/mesh/scheduler_cli.c
   ${NRF_DIR}/subsys/bluetooth/mesh/time_util.c
   ${NRF_DIR}/subsys/bluetooth/mesh/model_utils.c
-  ${ZEPHYR_BASE}/subsys/net/buf.c
   ../common/sched_test.c
   )
 
diff --git a/tests/subsys/bluetooth/mesh/scheduler_model/message_validity/prj.conf b/tests/subsys/bluetooth/mesh/scheduler_model/message_validity/prj.conf
index 480635a19b9d..09cc225d1395 100644
--- a/tests/subsys/bluetooth/mesh/scheduler_model/message_validity/prj.conf
+++ b/tests/subsys/bluetooth/mesh/scheduler_model/message_validity/prj.conf
@@ -9,3 +9,5 @@ CONFIG_ZTEST=y
 CONFIG_ZTEST_NEW_API=y
 CONFIG_TEST_RANDOM_GENERATOR=y
 CONFIG_ZTEST_MOCKING=y
+
+CONFIG_NET_BUF=y
diff --git a/tests/subsys/bluetooth/mesh/scheduler_model/timing/CMakeLists.txt b/tests/subsys/bluetooth/mesh/scheduler_model/timing/CMakeLists.txt
index 98f7fed3a511..9dcc16aef871 100644
--- a/tests/subsys/bluetooth/mesh/scheduler_model/timing/CMakeLists.txt
+++ b/tests/subsys/bluetooth/mesh/scheduler_model/timing/CMakeLists.txt
@@ -20,7 +20,6 @@ target_sources(app PRIVATE
   ${app_sources}
   ${NRF_DIR}/subsys/bluetooth/mesh/scheduler_srv.c
   ${NRF_DIR}/subsys/bluetooth/mesh/time_util.c
-  ${ZEPHYR_BASE}/subsys/net/buf.c
   ../common/sched_test.c
   )
 
diff --git a/tests/subsys/bluetooth/mesh/scheduler_model/timing/prj.conf b/tests/subsys/bluetooth/mesh/scheduler_model/timing/prj.conf
index 547ba1122804..e627fcbd2a65 100644
--- a/tests/subsys/bluetooth/mesh/scheduler_model/timing/prj.conf
+++ b/tests/subsys/bluetooth/mesh/scheduler_model/timing/prj.conf
@@ -8,3 +8,5 @@
 CONFIG_ZTEST=y
 CONFIG_ZTEST_NEW_API=y
 CONFIG_TEST_RANDOM_GENERATOR=y
+
+CONFIG_NET_BUF=y
diff --git a/tests/subsys/bluetooth/mesh/sensor_subsys/CMakeLists.txt b/tests/subsys/bluetooth/mesh/sensor_subsys/CMakeLists.txt
index 55f5f1839580..c605cd8739d0 100644
--- a/tests/subsys/bluetooth/mesh/sensor_subsys/CMakeLists.txt
+++ b/tests/subsys/bluetooth/mesh/sensor_subsys/CMakeLists.txt
@@ -18,7 +18,6 @@ target_sources(app PRIVATE
   ${app_sources}
   ${NRF_DIR}/subsys/bluetooth/mesh/sensor_types.c
   ${NRF_DIR}/subsys/bluetooth/mesh/sensor.c
-  ${ZEPHYR_BASE}/subsys/net/buf.c
   ${ZEPHYR_BASE}/subsys/bluetooth/mesh/msg.c
   )
 
diff --git a/tests/subsys/bluetooth/mesh/sensor_subsys/prj.conf b/tests/subsys/bluetooth/mesh/sensor_subsys/prj.conf
index 30c64c195ebd..e3369b3d56d4 100644
--- a/tests/subsys/bluetooth/mesh/sensor_subsys/prj.conf
+++ b/tests/subsys/bluetooth/mesh/sensor_subsys/prj.conf
@@ -8,3 +8,4 @@
 CONFIG_ZTEST=y
 CONFIG_ZTEST_NEW_API=y
 CONFIG_CBPRINTF_FP_SUPPORT=y
+CONFIG_NET_BUF=y
diff --git a/tests/subsys/bluetooth/mesh/silvair_enocean_model/CMakeLists.txt b/tests/subsys/bluetooth/mesh/silvair_enocean_model/CMakeLists.txt
index 3847a55211c8..0cdbe4c69d20 100644
--- a/tests/subsys/bluetooth/mesh/silvair_enocean_model/CMakeLists.txt
+++ b/tests/subsys/bluetooth/mesh/silvair_enocean_model/CMakeLists.txt
@@ -15,7 +15,6 @@ target_sources(app
     PRIVATE
     ${ZEPHYR_BASE}/../zephyr/subsys/bluetooth/common/addr.c
     ${ZEPHYR_BASE}/../nrf/subsys/bluetooth/mesh/vnd/silvair_enocean_srv.c
-    ${ZEPHYR_BASE}/subsys/net/buf.c
     )
 
 target_include_directories(app
diff --git a/tests/subsys/bluetooth/mesh/silvair_enocean_model/prj.conf b/tests/subsys/bluetooth/mesh/silvair_enocean_model/prj.conf
index e6e9df1cf5e7..8731ff95502c 100644
--- a/tests/subsys/bluetooth/mesh/silvair_enocean_model/prj.conf
+++ b/tests/subsys/bluetooth/mesh/silvair_enocean_model/prj.conf
@@ -8,3 +8,5 @@
 CONFIG_ZTEST=y
 CONFIG_ZTEST_NEW_API=y
 CONFIG_ZTEST_MOCKING=y
+
+CONFIG_NET_BUF=y
diff --git a/tests/subsys/bootloader/boot_chains/prj.conf b/tests/subsys/bootloader/boot_chains/prj.conf
new file mode 100644
index 000000000000..c5c73046947e
--- /dev/null
+++ b/tests/subsys/bootloader/boot_chains/prj.conf
@@ -0,0 +1 @@
+# Intentionally left empty.
diff --git a/tests/subsys/bootloader/boot_chains/src/main.c b/tests/subsys/bootloader/boot_chains/src/main.c
index 88a3139ec5d3..69aff5ad2f08 100644
--- a/tests/subsys/bootloader/boot_chains/src/main.c
+++ b/tests/subsys/bootloader/boot_chains/src/main.c
@@ -6,7 +6,9 @@
 
 #include <zephyr/kernel.h>
 
-void main(void)
+int main(void)
 {
 	printk("Hello World! %s\n", CONFIG_BOARD);
+
+	return 0;
 }
diff --git a/tests/subsys/event_manager_proxy/remote/main.c b/tests/subsys/event_manager_proxy/remote/main.c
index 2136ec41826d..770dc40a908d 100644
--- a/tests/subsys/event_manager_proxy/remote/main.c
+++ b/tests/subsys/event_manager_proxy/remote/main.c
@@ -23,7 +23,7 @@ static enum test_id cur_test_id;
 static unsigned int cur_test_pos;
 
 
-void main(void)
+int main(void)
 {
 	printk("Event Manager Proxy test remote_core started\n");
 
@@ -34,7 +34,7 @@ void main(void)
 	if (ret) {
 		LOG_ERR("Event Manager not initialized, err: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 	LOG_INF("Event manager initialized");
 
@@ -42,7 +42,7 @@ void main(void)
 	if (ret) {
 		LOG_ERR("Cannot add remote: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 	LOG_INF("Event proxy remote added");
 
@@ -58,13 +58,15 @@ void main(void)
 	if (ret) {
 		LOG_ERR("Cannot start event manager proxy: %d", ret);
 		__ASSERT_NO_MSG(false);
-		return;
+		return 0;
 	}
 
 	/* We do not have to wait for remotes here as we do not send any event that
 	 * would be fatal when missed.
 	 */
 	LOG_INF("Initialization finished successfully");
+
+	return 0;
 }
 
 static void proxy_direct_submit_pong_event(void)
diff --git a/tests/subsys/net/lib/azure_iot_hub/dps/src/azure_iot_hub_dps_test.c b/tests/subsys/net/lib/azure_iot_hub/dps/src/azure_iot_hub_dps_test.c
index 85e783c34269..89299209ecd8 100644
--- a/tests/subsys/net/lib/azure_iot_hub/dps/src/azure_iot_hub_dps_test.c
+++ b/tests/subsys/net/lib/azure_iot_hub/dps/src/azure_iot_hub_dps_test.c
@@ -46,6 +46,10 @@
 						"/api-version=2019-03-31"
 #define TEST_EXPECTED_USER_NAME_DEFAULT_LEN	(sizeof(TEST_EXPECTED_USER_NAME_DEFAULT) - 1)
 
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
+ */
 extern int unity_main(void);
 
 /* Pull in variables and functions from the DPS library. */
@@ -468,7 +472,9 @@ void test_on_publish_invalid_payload(void)
 	TEST_ASSERT_EQUAL(0, k_sem_take(&reg_failed_sem, K_SECONDS(2)));
 }
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/tests/subsys/net/lib/azure_iot_hub/iot_hub/src/azure_iot_hub_test.c b/tests/subsys/net/lib/azure_iot_hub/iot_hub/src/azure_iot_hub_test.c
index 4b5642d51906..3c6fbf3a009e 100644
--- a/tests/subsys/net/lib/azure_iot_hub/iot_hub/src/azure_iot_hub_test.c
+++ b/tests/subsys/net/lib/azure_iot_hub/iot_hub/src/azure_iot_hub_test.c
@@ -79,6 +79,10 @@ enum iot_hub_state {
 };
 
 /* Pull in variables and functions from the Azure IoT Hub library. */
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
+ */
 extern int unity_main(void);
 extern void iot_hub_state_set(enum iot_hub_state state);
 extern enum iot_hub_state iot_hub_state;
@@ -640,7 +644,9 @@ void test_azure_iot_hub_method_respond_mqtt_fail(void)
 	TEST_ASSERT_EQUAL(-ENXIO, azure_iot_hub_method_respond(&result));
 }
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/tests/subsys/net/lib/lwm2m_client_utils/src/connmon.c b/tests/subsys/net/lib/lwm2m_client_utils/src/connmon.c
index e881fb43a7ee..a8777fbe9cba 100644
--- a/tests/subsys/net/lib/lwm2m_client_utils/src/connmon.c
+++ b/tests/subsys/net/lib/lwm2m_client_utils/src/connmon.c
@@ -128,7 +128,7 @@ ZTEST(lwm2m_client_utils_connmon, test_modem_info_init_fail)
 	setup();
 
 	modem_info_init_fake.return_val = -1;
-	rc = lwm2m_init_connmon(NULL);
+	rc = lwm2m_init_connmon();
 	zassert_equal(modem_info_init_fake.call_count, 1, "Modem info init not called");
 	zassert_equal(rc, modem_info_init_fake.return_val, "wrong return value");
 }
@@ -140,7 +140,7 @@ ZTEST(lwm2m_client_utils_connmon, test_modem_info_params_init_fail)
 	setup();
 
 	modem_info_params_init_fake.return_val = -2;
-	rc = lwm2m_init_connmon(NULL);
+	rc = lwm2m_init_connmon();
 	zassert_equal(modem_info_params_init_fake.call_count, 1, "Info params init not called");
 	zassert_equal(rc, modem_info_params_init_fake.return_val, "wrong return value");
 }
@@ -149,7 +149,7 @@ ZTEST(lwm2m_client_utils_connmon, test_init)
 {
 	setup();
 
-	lwm2m_init_connmon(NULL);
+	lwm2m_init_connmon();
 	zassert_equal(lte_lc_register_handler_fake.call_count, 1);
 }
 
@@ -165,7 +165,7 @@ ZTEST(lwm2m_client_utils_connmon, test_connected)
 	lwm2m_set_s8_fake.custom_fake = set_s8_custom_fake;
 	modem_info_params_get_fake.custom_fake = copy_modem_info;
 	modem_info_rsrp_register_fake.custom_fake = copy_rsrp_handler;
-	lwm2m_init_connmon(NULL);
+	lwm2m_init_connmon();
 	evt.type = LTE_LC_EVT_NW_REG_STATUS;
 	evt.nw_reg_status = LTE_LC_NW_REG_REGISTERED_HOME;
 	handler(&evt);
@@ -191,7 +191,7 @@ ZTEST(lwm2m_client_utils_connmon, test_update_disconnected)
 	lte_lc_register_handler_fake.custom_fake = copy_event_handler;
 	lwm2m_set_string_fake.custom_fake = set_string_custom_fake;
 	modem_info_params_get_fake.custom_fake = copy_modem_info;
-	lwm2m_init_connmon(NULL);
+	lwm2m_init_connmon();
 	evt.type = LTE_LC_EVT_CELL_UPDATE;
 	handler(&evt);
 	k_sleep(K_MSEC(100));
@@ -208,7 +208,7 @@ ZTEST(lwm2m_client_utils_connmon, test_update)
 	lte_lc_register_handler_fake.custom_fake = copy_event_handler;
 	lwm2m_set_string_fake.custom_fake = set_string_custom_fake;
 	modem_info_params_get_fake.custom_fake = copy_modem_info;
-	lwm2m_init_connmon(NULL);
+	lwm2m_init_connmon();
 	evt.type = LTE_LC_EVT_NW_REG_STATUS;
 	evt.nw_reg_status = LTE_LC_NW_REG_REGISTERED_HOME;
 	handler(&evt);
@@ -237,7 +237,7 @@ ZTEST(lwm2m_client_utils_connmon, test_lte_mode_update)
 
 	lte_lc_register_handler_fake.custom_fake = copy_event_handler;
 	lwm2m_set_u8_fake.custom_fake = set_u8_custom_fake;
-	lwm2m_init_connmon(NULL);
+	lwm2m_init_connmon();
 	evt.type = LTE_LC_EVT_LTE_MODE_UPDATE;
 	evt.lte_mode = lte_mode;
 	handler(&evt);
diff --git a/tests/subsys/net/lib/lwm2m_client_utils/src/location_assistance.c b/tests/subsys/net/lib/lwm2m_client_utils/src/location_assistance.c
index ac9cefb9522c..08d9b1d94c69 100644
--- a/tests/subsys/net/lib/lwm2m_client_utils/src/location_assistance.c
+++ b/tests/subsys/net/lib/lwm2m_client_utils/src/location_assistance.c
@@ -47,7 +47,7 @@ static struct nrf_modem_gnss_agps_data_frame agps_req = {
 
 static struct lwm2m_ctx client_ctx;
 
-static int suite_setup(const struct device *dev)
+static int suite_setup(void)
 {
 	lwm2m_register_obj_fake.custom_fake = fake_lwm2m_register_obj;
 
@@ -71,7 +71,7 @@ ZTEST(lwm2m_client_utils_location_assistance, test_agps_send)
 
 	rc = location_assistance_agps_request_send(&client_ctx, true);
 	zassert_equal(rc, 0, "Error %d", rc);
-	zassert_equal(lwm2m_send_fake.call_count, 1, "Request not sent");
+	zassert_equal(lwm2m_send_cb_fake.call_count, 1, "Request not sent");
 
 	gnss_obj->resources[GNSS_ASSIST_ASSIST_DATA].post_write_cb(0, GNSS_ASSIST_ASSIST_DATA, 0,
 								   buf, 8, true, 8);
@@ -91,7 +91,7 @@ ZTEST(lwm2m_client_utils_location_assistance, test_pgps_send)
 
 	rc = location_assistance_pgps_request_send(&client_ctx, true);
 	zassert_equal(rc, 0, "Error %d", rc);
-	zassert_equal(lwm2m_send_fake.call_count, 1, "Request not sent");
+	zassert_equal(lwm2m_send_cb_fake.call_count, 1, "Request not sent");
 
 	gnss_obj->resources[GNSS_ASSIST_ASSIST_DATA].post_write_cb(0, GNSS_ASSIST_ASSIST_DATA, 0,
 								   buf, 8, true, 8);
@@ -114,7 +114,7 @@ ZTEST(lwm2m_client_utils_location_assistance, test_simultaneous_send)
 
 	rc = location_assistance_agps_request_send(&client_ctx, true);
 	zassert_equal(rc, 0, "Error %d", rc);
-	zassert_equal(lwm2m_send_fake.call_count, 1, "Request not sent");
+	zassert_equal(lwm2m_send_cb_fake.call_count, 1, "Request not sent");
 
 	rc = location_assistance_pgps_request_send(&client_ctx, true);
 	zassert_equal(rc, -EAGAIN, "Error %d", rc);
@@ -126,7 +126,7 @@ ZTEST(lwm2m_client_utils_location_assistance, test_simultaneous_send)
 
 	rc = location_assistance_pgps_request_send(&client_ctx, true);
 	zassert_equal(rc, 0, "Error %d", rc);
-	zassert_equal(lwm2m_send_fake.call_count, 2, "Request not sent");
+	zassert_equal(lwm2m_send_cb_fake.call_count, 2, "Request not sent");
 
 	gnss_obj->resources[GNSS_ASSIST_ASSIST_DATA].post_write_cb(0, GNSS_ASSIST_ASSIST_DATA, 0,
 								   buf, 8, true, 8);
@@ -143,7 +143,7 @@ ZTEST(lwm2m_client_utils_location_assistance, test_ground_fix_send)
 	rc = location_assistance_ground_fix_request_send(&client_ctx, true);
 
 	zassert_equal(rc, 0, "Error %d", rc);
-	zassert_equal(lwm2m_send_fake.call_count, 1, "Request not sent");
+	zassert_equal(lwm2m_send_cb_fake.call_count, 1, "Request not sent");
 }
 
 ZTEST(lwm2m_client_utils_location_assistance, test_temporary_failure)
@@ -164,7 +164,7 @@ ZTEST(lwm2m_client_utils_location_assistance, test_temporary_failure)
 
 	rc = location_assistance_agps_request_send(&client_ctx, true);
 	zassert_equal(rc, 0, "Error %d", rc);
-	zassert_equal(lwm2m_send_fake.call_count, 1, "Request not sent");
+	zassert_equal(lwm2m_send_cb_fake.call_count, 1, "Request not sent");
 
 	gnss_obj->resources[GNSS_ASSIST_RESULT_CODE].post_write_cb(0, GNSS_ASSIST_RESULT_CODE, 0,
 								   resbuf, 4, true, 4);
@@ -197,7 +197,7 @@ ZTEST(lwm2m_client_utils_location_assistance, test_zzzpermanent_failure)
 
 	rc = location_assistance_agps_request_send(&client_ctx, true);
 	zassert_equal(rc, 0, "Error %d", rc);
-	zassert_equal(lwm2m_send_fake.call_count, 1, "Request not sent");
+	zassert_equal(lwm2m_send_cb_fake.call_count, 1, "Request not sent");
 
 	gnss_obj->resources[GNSS_ASSIST_RESULT_CODE].post_write_cb(0, GNSS_ASSIST_RESULT_CODE, 0,
 								   resbuf, 4, true, 4);
diff --git a/tests/subsys/net/lib/lwm2m_client_utils/src/stubs.c b/tests/subsys/net/lib/lwm2m_client_utils/src/stubs.c
index 41946caee737..312a5bf654fd 100644
--- a/tests/subsys/net/lib/lwm2m_client_utils/src/stubs.c
+++ b/tests/subsys/net/lib/lwm2m_client_utils/src/stubs.c
@@ -32,8 +32,8 @@ DEFINE_FAKE_VALUE_FUNC(int, lwm2m_get_bool, const struct lwm2m_obj_path *, bool
 DEFINE_FAKE_VALUE_FUNC(int, lwm2m_set_opaque, const struct lwm2m_obj_path *, const char *,
 		       uint16_t);
 DEFINE_FAKE_VALUE_FUNC(int, lwm2m_set_string, const struct lwm2m_obj_path *, const char*);
-DEFINE_FAKE_VALUE_FUNC(int, lwm2m_send, struct lwm2m_ctx *,
-		       const struct lwm2m_obj_path *, uint8_t, bool);
+DEFINE_FAKE_VALUE_FUNC(int, lwm2m_send_cb, struct lwm2m_ctx *,
+		       const struct lwm2m_obj_path *, uint8_t, lwm2m_send_cb_t);
 DEFINE_FAKE_VALUE_FUNC(int, lwm2m_delete_object_inst, const struct lwm2m_obj_path *);
 DEFINE_FAKE_VALUE_FUNC(int, lwm2m_register_delete_callback, uint16_t,
 		       lwm2m_engine_user_cb_t);
diff --git a/tests/subsys/net/lib/lwm2m_client_utils/src/stubs.h b/tests/subsys/net/lib/lwm2m_client_utils/src/stubs.h
index 3072820d5b34..2def1abbea21 100644
--- a/tests/subsys/net/lib/lwm2m_client_utils/src/stubs.h
+++ b/tests/subsys/net/lib/lwm2m_client_utils/src/stubs.h
@@ -27,8 +27,8 @@ DECLARE_FAKE_VALUE_FUNC(int, lwm2m_get_bool, const struct lwm2m_obj_path *, bool
 DECLARE_FAKE_VALUE_FUNC(int, lwm2m_set_opaque, const struct lwm2m_obj_path *, const char *,
 			uint16_t);
 DECLARE_FAKE_VALUE_FUNC(int, lwm2m_set_string, const struct lwm2m_obj_path *, const char *)
-DECLARE_FAKE_VALUE_FUNC(int, lwm2m_send, struct lwm2m_ctx *,
-			const struct lwm2m_obj_path *, uint8_t, bool);
+DECLARE_FAKE_VALUE_FUNC(int, lwm2m_send_cb, struct lwm2m_ctx *,
+			const struct lwm2m_obj_path *, uint8_t, lwm2m_send_cb_t);
 DECLARE_FAKE_VALUE_FUNC(int, lwm2m_delete_object_inst, const struct lwm2m_obj_path *);
 DECLARE_FAKE_VALUE_FUNC(int, lwm2m_register_delete_callback, uint16_t,
 			lwm2m_engine_user_cb_t);
@@ -116,7 +116,7 @@ DECLARE_FAKE_VALUE_FUNC(int, at_params_list_init, struct at_param_list *, size_t
 	FUNC(lwm2m_set_s32)                             \
 	FUNC(lwm2m_set_opaque)                          \
 	FUNC(lwm2m_set_string)                          \
-	FUNC(lwm2m_send)                                \
+	FUNC(lwm2m_send_cb)                             \
 	FUNC(lwm2m_delete_object_inst)                  \
 	FUNC(lwm2m_register_delete_callback)            \
 	FUNC(lwm2m_register_create_callback)            \
diff --git a/tests/subsys/net/lib/mqtt_helper/src/mqtt_helper_test.c b/tests/subsys/net/lib/mqtt_helper/src/mqtt_helper_test.c
index 171f80b0221f..f245e42fafc6 100644
--- a/tests/subsys/net/lib/mqtt_helper/src/mqtt_helper_test.c
+++ b/tests/subsys/net/lib/mqtt_helper/src/mqtt_helper_test.c
@@ -38,6 +38,10 @@ extern struct mqtt_client mqtt_client;
 extern enum mqtt_state mqtt_state;
 extern struct k_sem connection_poll_sem;
 extern k_tid_t mqtt_helper_thread;
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
+ */
 extern int unity_main(void);
 extern enum mqtt_state mqtt_state_get(void);
 extern void mqtt_state_set(enum mqtt_state state);
@@ -595,7 +599,9 @@ void test_mqtt_helper_poll_loop_pollerr(void)
 	mqtt_helper_poll_loop();
 }
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/tests/subsys/net/lib/wifi_credentials/src/main.c b/tests/subsys/net/lib/wifi_credentials/src/main.c
index 0de70ee3ddb9..066a7cd43aa9 100644
--- a/tests/subsys/net/lib/wifi_credentials/src/main.c
+++ b/tests/subsys/net/lib/wifi_credentials/src/main.c
@@ -308,10 +308,16 @@ void test_storage_limit(void)
 	wifi_credentials_for_each_ssid(verify_ssid_cache_cb, NULL);
 }
 
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
+ */
 extern int unity_main(void);
 
-void main(void)
+int main(void)
 {
 	/* use the runner from test_runner_generate() */
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/tests/subsys/net/lib/wifi_credentials_backend_psa/src/main.c b/tests/subsys/net/lib/wifi_credentials_backend_psa/src/main.c
index 85dd34c4395f..c7ba62cc8ed6 100644
--- a/tests/subsys/net/lib/wifi_credentials_backend_psa/src/main.c
+++ b/tests/subsys/net/lib/wifi_credentials_backend_psa/src/main.c
@@ -164,10 +164,16 @@ void test_delete(void)
 	TEST_ASSERT_EQUAL(2, psa_ps_remove_fake.call_count);
 }
 
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
+ */
 extern int unity_main(void);
 
-void main(void)
+int main(void)
 {
 	/* use the runner from test_runner_generate() */
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/tests/subsys/net/lib/wifi_credentials_backend_settings/src/main.c b/tests/subsys/net/lib/wifi_credentials_backend_settings/src/main.c
index 9722a0b7c1a6..0ee60c5ebec8 100644
--- a/tests/subsys/net/lib/wifi_credentials_backend_settings/src/main.c
+++ b/tests/subsys/net/lib/wifi_credentials_backend_settings/src/main.c
@@ -228,10 +228,16 @@ void test_delete(void)
 	TEST_ASSERT_EQUAL(1, settings_delete_fake.call_count);
 }
 
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
+ */
 extern int unity_main(void);
 
-void main(void)
+int main(void)
 {
 	/* use the runner from test_runner_generate() */
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/tests/subsys/zigbee/osif/nvram/boards/nrf52833dk_nrf52833.overlay b/tests/subsys/zigbee/osif/nvram/boards/nrf52833dk_nrf52833.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/tests/subsys/zigbee/osif/nvram/boards/nrf52833dk_nrf52833.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/tests/subsys/zigbee/osif/nvram/boards/nrf52840dk_nrf52840.overlay b/tests/subsys/zigbee/osif/nvram/boards/nrf52840dk_nrf52840.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/tests/subsys/zigbee/osif/nvram/boards/nrf52840dk_nrf52840.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/tests/subsys/zigbee/osif/nvram/boards/nrf5340dk_nrf5340_cpuapp.overlay b/tests/subsys/zigbee/osif/nvram/boards/nrf5340dk_nrf5340_cpuapp.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/tests/subsys/zigbee/osif/nvram/boards/nrf5340dk_nrf5340_cpuapp.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/tests/subsys/zigbee/osif/timer_counter/boards/nrf52833dk_nrf52833.overlay b/tests/subsys/zigbee/osif/timer_counter/boards/nrf52833dk_nrf52833.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/tests/subsys/zigbee/osif/timer_counter/boards/nrf52833dk_nrf52833.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/tests/subsys/zigbee/osif/timer_counter/boards/nrf52840dk_nrf52840.overlay b/tests/subsys/zigbee/osif/timer_counter/boards/nrf52840dk_nrf52840.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/tests/subsys/zigbee/osif/timer_counter/boards/nrf52840dk_nrf52840.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/tests/subsys/zigbee/osif/timer_counter/boards/nrf5340dk_nrf5340_cpuapp.overlay b/tests/subsys/zigbee/osif/timer_counter/boards/nrf5340dk_nrf5340_cpuapp.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/tests/subsys/zigbee/osif/timer_counter/boards/nrf5340dk_nrf5340_cpuapp.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/tests/subsys/zigbee/osif/timer_counter/prj.conf b/tests/subsys/zigbee/osif/timer_counter/prj.conf
index 430aa95c954f..cd4d9df011d8 100644
--- a/tests/subsys/zigbee/osif/timer_counter/prj.conf
+++ b/tests/subsys/zigbee/osif/timer_counter/prj.conf
@@ -6,4 +6,3 @@
 
 CONFIG_ZTEST=y
 CONFIG_COUNTER=y
-CONFIG_COUNTER_TIMER2=y
diff --git a/tests/subsys/zigbee/zboss_api/alarm_api/boards/nrf52833dk_nrf52833.overlay b/tests/subsys/zigbee/zboss_api/alarm_api/boards/nrf52833dk_nrf52833.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/tests/subsys/zigbee/zboss_api/alarm_api/boards/nrf52833dk_nrf52833.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/tests/subsys/zigbee/zboss_api/alarm_api/boards/nrf52840dk_nrf52840.overlay b/tests/subsys/zigbee/zboss_api/alarm_api/boards/nrf52840dk_nrf52840.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/tests/subsys/zigbee/zboss_api/alarm_api/boards/nrf52840dk_nrf52840.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/tests/subsys/zigbee/zboss_api/alarm_api/boards/nrf5340dk_nrf5340_cpuapp.overlay b/tests/subsys/zigbee/zboss_api/alarm_api/boards/nrf5340dk_nrf5340_cpuapp.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/tests/subsys/zigbee/zboss_api/alarm_api/boards/nrf5340dk_nrf5340_cpuapp.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/tests/subsys/zigbee/zboss_api/callback_api/boards/nrf52833dk_nrf52833.overlay b/tests/subsys/zigbee/zboss_api/callback_api/boards/nrf52833dk_nrf52833.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/tests/subsys/zigbee/zboss_api/callback_api/boards/nrf52833dk_nrf52833.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/tests/subsys/zigbee/zboss_api/callback_api/boards/nrf52840dk_nrf52840.overlay b/tests/subsys/zigbee/zboss_api/callback_api/boards/nrf52840dk_nrf52840.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/tests/subsys/zigbee/zboss_api/callback_api/boards/nrf52840dk_nrf52840.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/tests/subsys/zigbee/zboss_api/callback_api/boards/nrf5340dk_nrf5340_cpuapp.overlay b/tests/subsys/zigbee/zboss_api/callback_api/boards/nrf5340dk_nrf5340_cpuapp.overlay
new file mode 100644
index 000000000000..62b6a462f7d1
--- /dev/null
+++ b/tests/subsys/zigbee/zboss_api/callback_api/boards/nrf5340dk_nrf5340_cpuapp.overlay
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+/ {
+	chosen {
+		ncs,zigbee-timer = &timer2;
+	};
+};
+
+&timer2 {
+	status = "okay";
+};
diff --git a/tests/tfm/tfm_psa_test/src/main.c b/tests/tfm/tfm_psa_test/src/main.c
index 81abfc890eb6..7c385cb37a3d 100644
--- a/tests/tfm/tfm_psa_test/src/main.c
+++ b/tests/tfm/tfm_psa_test/src/main.c
@@ -11,7 +11,9 @@
 /* Run the PSA test suite */
 void psa_test(void);
 
-void main(void)
+int main(void)
 {
 	psa_test();
+
+	return 0;
 }
diff --git a/tests/tfm/tfm_regression_test/src/main.c b/tests/tfm/tfm_regression_test/src/main.c
index ffc820d3416f..41c58c537722 100644
--- a/tests/tfm/tfm_regression_test/src/main.c
+++ b/tests/tfm/tfm_regression_test/src/main.c
@@ -6,8 +6,10 @@
 
 #include <zephyr/kernel.h>
 
-void main(void)
+int main(void)
 {
 	printk("Should not be printed, expected TF-M's NS application to be run instead.\n");
 	k_panic();
+
+	return 0;		/* unreachable */
 }
diff --git a/tests/unity/example_test/src/example_test.c b/tests/unity/example_test/src/example_test.c
index b5645fa68702..ec3e92567c01 100644
--- a/tests/unity/example_test/src/example_test.c
+++ b/tests/unity/example_test/src/example_test.c
@@ -39,13 +39,15 @@ void test_uut_init_with_param_check(void)
 	TEST_ASSERT_EQUAL(-1, err);
 }
 
-/* It is required to be added to each test. That is because unity is using
- * different main signature (returns int) and zephyr expects main which does
- * not return value.
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
  */
 extern int unity_main(void);
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/tests/unity/wrap_test/src/wrap_test.c b/tests/unity/wrap_test/src/wrap_test.c
index 3b93bcbd8277..7d7de7c9ca40 100644
--- a/tests/unity/wrap_test/src/wrap_test.c
+++ b/tests/unity/wrap_test/src/wrap_test.c
@@ -86,13 +86,15 @@ void test_word_exclude(void)
 	call_exclude_word_fn();
 }
 
-/* It is required to be added to each test. That is because unity is using
- * different main signature (returns int) and zephyr expects main which does
- * not return value.
+/* It is required to be added to each test. That is because unity's
+ * main may return nonzero, while zephyr's main currently must
+ * return 0 in all cases (other values are reserved).
  */
 extern int unity_main(void);
 
-void main(void)
+int main(void)
 {
 	(void)unity_main();
+
+	return 0;
 }
diff --git a/west.yml b/west.yml
index 15bb2aa6e2c1..f1c10ef79e71 100644
--- a/west.yml
+++ b/west.yml
@@ -59,7 +59,7 @@ manifest:
     # https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/guides/modules.html
     - name: zephyr
       repo-path: sdk-zephyr
-      revision: 74c7bca86e6a7d590333681eef90e159d79bcfe8
+      revision: b54c8baeeafb3d6e9eef6092c5d88a6771548460
       import:
         # In addition to the zephyr repository itself, NCS also
         # imports the contents of zephyr/west.yml at the above
@@ -110,7 +110,7 @@ manifest:
     - name: hostap
       repo-path: sdk-hostap
       path: modules/lib/hostap
-      revision: ff98ecf541f1e43a9e89e4d47f24e7c59c65f5fe
+      revision: ec4a32a3a7037603aa87dd5b31622141ceddf32b
       userdata:
         ncs:
           upstream-url: https://w1.fi/cgit/hostap/
@@ -118,7 +118,7 @@ manifest:
           compare-by-default: false
     - name: mcuboot
       repo-path: sdk-mcuboot
-      revision: c78d59dbe8ec48cfbdff9a0bfc12f25b90c73d2f
+      revision: 3b7c7fb9ac786bf4d06aac5a19b5e6153a802584
       path: bootloader/mcuboot
     - name: qcbor
       url: https://github.com/laurencelundblade/QCBOR.git
@@ -131,7 +131,7 @@ manifest:
     - name: nrfxlib
       repo-path: sdk-nrfxlib
       path: nrfxlib
-      revision: 9cb73143fb543d3eefeeb356ae335a7e4c756512
+      revision: 2fa09cf5566a3ec04de696b9e967aaa8bd370f86
     - name: trusted-firmware-m
       repo-path: sdk-trusted-firmware-m
       path: modules/tee/tf-m/trusted-firmware-m
@@ -139,7 +139,7 @@ manifest:
     - name: matter
       repo-path: sdk-connectedhomeip
       path: modules/lib/matter
-      revision: 032a0a95c5b6c761b35cd73e98e41f56f59fa5f0
+      revision: 0809166d47b61feb205acecb100cf5be7558b9e1
       submodules:
         - name: nlio
           path: third_party/nlio/repo
@@ -179,7 +179,7 @@ manifest:
           compare-by-default: false
     - name: homekit
       repo-path: sdk-homekit
-      revision: 7d3f3a3e098d64fbf804fc1edfd033ded56d161d
+      revision: 286b97f3a7514bc4924818611475ae5be0496ed1
       groups:
         - homekit
     - name: find-my
@@ -223,7 +223,7 @@ manifest:
       remote: throwtheswitch
     - name: memfault-firmware-sdk
       path: modules/lib/memfault-firmware-sdk
-      revision: 0.42.1
+      revision: 0.43.1
       remote: memfault
     - name: ant
       repo-path: sdk-ant