diff --git a/connectivity/FEATURE_BLE/libraries/TARGET_CORDIO_LL/stack/controller/sources/ble/lctr/lctr_main_iso.c b/connectivity/FEATURE_BLE/libraries/TARGET_CORDIO_LL/stack/controller/sources/ble/lctr/lctr_main_iso.c
index 369609871c6..bf81eb6df21 100644
--- a/connectivity/FEATURE_BLE/libraries/TARGET_CORDIO_LL/stack/controller/sources/ble/lctr/lctr_main_iso.c
+++ b/connectivity/FEATURE_BLE/libraries/TARGET_CORDIO_LL/stack/controller/sources/ble/lctr/lctr_main_iso.c
@@ -988,7 +988,7 @@ uint8_t LctrIsoReadTestCounter(uint16_t handle, LlIsoTestCtrs_t *pStats)
 /*************************************************************************************************/
 uint8_t LctrIsoTestEnd(uint16_t handle, LlIsoTestCtrs_t *pStats)
 {
-  uint8_t status;
+  uint8_t status = LL_ERROR_CODE_UNSPECIFIED_ERROR;
   lctrCisCtx_t *pCisCtx;
   lctrBisCtx_t *pBisCtx;
 
diff --git a/connectivity/cellular/include/cellular/framework/AT/AT_CellularDevice.h b/connectivity/cellular/include/cellular/framework/AT/AT_CellularDevice.h
index 07a5f90dad2..3d9d2c8eac6 100755
--- a/connectivity/cellular/include/cellular/framework/AT/AT_CellularDevice.h
+++ b/connectivity/cellular/include/cellular/framework/AT/AT_CellularDevice.h
@@ -67,7 +67,7 @@ class AT_CellularDevice : public CellularDevice {
     };
 
 public:
-    AT_CellularDevice(FileHandle *fh, char *delim = "\r");
+    AT_CellularDevice(FileHandle *fh, const char *delim = "\r");
     virtual ~AT_CellularDevice();
 
     virtual nsapi_error_t clear();
diff --git a/connectivity/cellular/source/framework/AT/AT_CellularDevice.cpp b/connectivity/cellular/source/framework/AT/AT_CellularDevice.cpp
index e3fd5b551a3..4798576898a 100644
--- a/connectivity/cellular/source/framework/AT/AT_CellularDevice.cpp
+++ b/connectivity/cellular/source/framework/AT/AT_CellularDevice.cpp
@@ -39,7 +39,7 @@ using namespace std::chrono_literals;
 #define DEFAULT_AT_TIMEOUT 1s // at default timeout
 const int MAX_SIM_RESPONSE_LENGTH = 16;
 
-AT_CellularDevice::AT_CellularDevice(FileHandle *fh, char *delim):
+AT_CellularDevice::AT_CellularDevice(FileHandle *fh, const char *delim):
     CellularDevice(),
     _at(fh, _queue, DEFAULT_AT_TIMEOUT, delim),
 #if MBED_CONF_CELLULAR_USE_SMS
diff --git a/connectivity/drivers/cellular/GEMALTO/CINTERION/GEMALTO_CINTERION_CellularStack.cpp b/connectivity/drivers/cellular/GEMALTO/CINTERION/GEMALTO_CINTERION_CellularStack.cpp
index a78e89a062b..75b2fae7d58 100644
--- a/connectivity/drivers/cellular/GEMALTO/CINTERION/GEMALTO_CINTERION_CellularStack.cpp
+++ b/connectivity/drivers/cellular/GEMALTO/CINTERION/GEMALTO_CINTERION_CellularStack.cpp
@@ -444,7 +444,7 @@ nsapi_size_or_error_t GEMALTO_CINTERION_CellularStack::socket_recvfrom_impl(Cell
         if (address) {
             char *ip_start = ip_address;
             char *ip_stop;
-            char *port_start;
+            char *port_start = (char *)0xDEADBEEF;
             if (_stack_type == IPV6_STACK) {
                 ip_start++; // skip '['
                 ip_stop = strchr(ip_address, ']');
diff --git a/connectivity/nanostack/sal-stack-nanostack/source/6LoWPAN/adaptation_interface.c b/connectivity/nanostack/sal-stack-nanostack/source/6LoWPAN/adaptation_interface.c
index 55904778f07..fb7027bf1a3 100644
--- a/connectivity/nanostack/sal-stack-nanostack/source/6LoWPAN/adaptation_interface.c
+++ b/connectivity/nanostack/sal-stack-nanostack/source/6LoWPAN/adaptation_interface.c
@@ -1554,7 +1554,7 @@ int8_t lowpan_adaptation_interface_tx_confirm(protocol_interface_info_entry_t *c
 
     //Check first
     fragmenter_tx_entry_t *tx_ptr;
-    bool active_direct_confirm;
+    bool active_direct_confirm = false;
     if (lowpan_active_tx_handle_verify(confirm->msduHandle, interface_ptr->active_broadcast_tx_buf.buf)) {
         active_direct_confirm = true;
         tx_ptr = &interface_ptr->active_broadcast_tx_buf;
diff --git a/platform/source/mbed_board.c b/platform/source/mbed_board.c
index 47c92e06145..0f9553fdb14 100644
--- a/platform/source/mbed_board.c
+++ b/platform/source/mbed_board.c
@@ -28,8 +28,8 @@ WEAK MBED_NORETURN void mbed_die(void)
 #if !defined(TARGET_EFM32)
     core_util_critical_section_enter();
 #endif
-    gpio_t led_err;
 #ifdef LED1
+    gpio_t led_err;
     gpio_init_out(&led_err, LED1);
 #endif
 
diff --git a/storage/kvstore/tdbstore/source/TDBStore.cpp b/storage/kvstore/tdbstore/source/TDBStore.cpp
index 50f490cf370..2003483af69 100644
--- a/storage/kvstore/tdbstore/source/TDBStore.cpp
+++ b/storage/kvstore/tdbstore/source/TDBStore.cpp
@@ -1490,7 +1490,7 @@ int TDBStore::check_erase_before_write(uint8_t area, uint32_t offset, uint32_t s
     uint32_t end_offset;
     while (size) {
         uint32_t dist, offset_from_start;
-        int ret;
+        // int ret;
         offset_in_erase_unit(area, offset, offset_from_start, dist);
         uint32_t chunk = std::min(size, dist);
 
diff --git a/targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/spi_api.c b/targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/spi_api.c
index 3cd900edca1..ec4a68886ab 100644
--- a/targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/spi_api.c
+++ b/targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/spi_api.c
@@ -212,7 +212,7 @@ void spi_get_capabilities(PinName ssel, bool slave, spi_capabilities_t *cap)
 
     // check if given ssel pin is in the cs pinmap
     const PinMap *cs_pins = spi_master_cs_pinmap();
-    PinName pin = NC;
+    // PinName pin = NC;
     while (cs_pins->pin != NC) {
         if (cs_pins->pin == ssel) {
 #if DEVICE_SPISLAVE