diff --git a/include/zephyr/devicetree/fixed-partitions.h b/include/zephyr/devicetree/fixed-partitions.h
index 14bb96bfc59..d9860f69d5a 100644
--- a/include/zephyr/devicetree/fixed-partitions.h
+++ b/include/zephyr/devicetree/fixed-partitions.h
@@ -131,7 +131,9 @@ extern "C" {
  * node containing it.
  */
 #define DT_FIXED_PARTITION_ADDR(node_id)                                                           \
-	(DT_REG_ADDR(DT_MEM_FROM_FIXED_PARTITION(node_id)) + DT_REG_ADDR(node_id))
+	(DT_REG_ADDR(node_id) + (DT_REG_ADDR(COND_CODE_1(                                          \
+		DT_NODE_EXISTS(DT_MEM_FROM_FIXED_PARTITION(node_id)),                              \
+		    (DT_MEM_FROM_FIXED_PARTITION(node_id)), (DT_GPARENT(node_id))))))
 
 /**
  * @brief Test if fixed-subpartitions compatible node exists
@@ -160,7 +162,7 @@ extern "C" {
  */
 #define DT_MTD_FROM_FIXED_SUBPARTITION(node_id)                                                    \
 	COND_CODE_1(DT_NODE_EXISTS(DT_MEM_FROM_FIXED_SUBPARTITION(node_id)),                       \
-		    (DT_PARENT(DT_MEM_FROM_FIXED_SUBPARTITION(node_id))), (DT_GPARENT(node_id)))
+	     (DT_PARENT(DT_MEM_FROM_FIXED_SUBPARTITION(node_id))), (DT_GPARENT(DT_PARENT(node_id))))
 
 /**
  * @brief Get the absolute address of a fixed subpartition
@@ -207,7 +209,9 @@ extern "C" {
  * node containing it.
  */
 #define DT_FIXED_SUBPARTITION_ADDR(node_id)                                                        \
-	(DT_REG_ADDR(DT_MEM_FROM_FIXED_SUBPARTITION(node_id)) + DT_REG_ADDR(node_id))
+	(DT_REG_ADDR(node_id) + (DT_REG_ADDR(COND_CODE_1(                                          \
+		DT_NODE_EXISTS(DT_MEM_FROM_FIXED_SUBPARTITION(node_id)),                           \
+		    (DT_MEM_FROM_FIXED_SUBPARTITION(node_id)), (DT_GPARENT(DT_PARENT(node_id)))))))
 
 /**
  * @}
diff --git a/include/zephyr/storage/flash_map.h b/include/zephyr/storage/flash_map.h
index f62f1c21718..91175068541 100644
--- a/include/zephyr/storage/flash_map.h
+++ b/include/zephyr/storage/flash_map.h
@@ -353,14 +353,17 @@ uint8_t flash_area_erased_val(const struct flash_area *fa);
 #else
 
 /**
- * Returns non-0 value if fixed-partition of given DTS node label exists.
+ * Returns non-0 value if fixed-partition as well as fixed-subpartition of given
+ * DTS node label exists.
  *
  * @param label DTS node label
  *
  * @return non-0 if fixed-partition node exists and is enabled;
  *	   0 if node does not exist, is not enabled or is not fixed-partition.
  */
-#define FIXED_PARTITION_EXISTS(label) DT_FIXED_PARTITION_EXISTS(DT_NODELABEL(label))
+#define FIXED_PARTITION_EXISTS(label) \
+	UTIL_OR(DT_FIXED_PARTITION_EXISTS(DT_NODELABEL(label)), \
+		DT_FIXED_SUBPARTITION_EXISTS(DT_NODELABEL(label)))
 
 /**
  * Get flash area ID from fixed-partition DTS node label
@@ -372,7 +375,7 @@ uint8_t flash_area_erased_val(const struct flash_area *fa);
 #define FIXED_PARTITION_ID(label) DT_FIXED_PARTITION_ID(DT_NODELABEL(label))
 
 /**
- * Get fixed-partition offset from DTS node label
+ * Get fixed-partition as well as fixed-subpartition offset from DTS node label
  *
  * @param label DTS node label of a partition
  *
@@ -380,6 +383,30 @@ uint8_t flash_area_erased_val(const struct flash_area *fa);
  */
 #define FIXED_PARTITION_OFFSET(label) DT_REG_ADDR(DT_NODELABEL(label))
 
+/**
+ * Get fixed-partition as well as fixed-subpartition address from DTS node label
+ *
+ * @param label DTS node label of a partition or subpartition
+ *
+ * @return fixed-partition address, as defined for the partition in DTS.
+ */
+#define FIXED_PARTITION_ADDRESS(label) \
+	(COND_CODE_1(DT_FIXED_SUBPARTITION_EXISTS(DT_NODELABEL(label)), \
+		(DT_FIXED_SUBPARTITION_ADDR(DT_NODELABEL(label))), \
+		(DT_FIXED_PARTITION_ADDR(DT_NODELABEL(label)))))
+
+/**
+ * Get fixed-partition as well as fixed-subpartition address from DTS node
+ *
+ * @param node DTS node of a partition
+ *
+ * @return fixed-partition address, as defined for the partition in DTS.
+ */
+#define FIXED_PARTITION_NODE_ADDRESS(node) \
+	(COND_CODE_1(DT_FIXED_SUBPARTITION_EXISTS(node), \
+		(DT_FIXED_SUBPARTITION_ADDR(node)), \
+		(DT_FIXED_PARTITION_ADDR(node))))
+
 /**
  * Get fixed-partition offset from DTS node
  *
@@ -425,8 +452,10 @@ uint8_t flash_area_erased_val(const struct flash_area *fa);
  * @return Pointer to a device.
  */
 #define FIXED_PARTITION_DEVICE(label) \
-	DEVICE_DT_GET(DT_MTD_FROM_FIXED_PARTITION(DT_NODELABEL(label)))
-
+	DEVICE_DT_GET(COND_CODE_1( \
+		DT_FIXED_SUBPARTITION_EXISTS(DT_NODELABEL(label)), \
+			(DT_MTD_FROM_FIXED_SUBPARTITION(DT_NODELABEL(label))), \
+			(DT_MTD_FROM_FIXED_PARTITION(DT_NODELABEL(label)))))
 /**
  * Get device pointer for device the area/partition resides on
  *
@@ -435,7 +464,10 @@ uint8_t flash_area_erased_val(const struct flash_area *fa);
  * @return Pointer to a device.
  */
 #define FIXED_PARTITION_NODE_DEVICE(node) \
-	DEVICE_DT_GET(DT_MTD_FROM_FIXED_PARTITION(node))
+	DEVICE_DT_GET(COND_CODE_1( \
+		DT_FIXED_SUBPARTITION_EXISTS(node), \
+			(DT_MTD_FROM_FIXED_SUBPARTITION(node)), \
+			(DT_MTD_FROM_FIXED_PARTITION(node))))
 
 /**
  * Get pointer to flash_area object by partition label
@@ -471,6 +503,22 @@ DT_FOREACH_STATUS_OKAY(fixed_partitions, FOR_EACH_PARTITION_TABLE)
 #undef DECLARE_PARTITION
 #undef DECLARE_PARTITION_0
 #undef FOR_EACH_PARTITION_TABLE
+
+#define FIXED_SUBPARTITION_1(node) FIXED_SUBPARTITION_0(DT_DEP_ORD(node))
+#define FIXED_SUBPARTITION_0(ord)						\
+	((const struct flash_area *)&DT_CAT(global_fixed_subpartition_ORD_, ord))
+
+#define DECLARE_SUBPARTITION(node) DECLARE_SUBPARTITION_0(DT_DEP_ORD(node))
+#define DECLARE_SUBPARTITION_0(ord)						\
+	extern const struct flash_area DT_CAT(global_fixed_subpartition_ORD_, ord);
+#define FOR_EACH_SUBPARTITION_TABLE(table) DT_FOREACH_CHILD(table, DECLARE_SUBPARTITION)
+
+/* Generate declarations */
+DT_FOREACH_STATUS_OKAY(fixed_subpartitions, FOR_EACH_SUBPARTITION_TABLE)
+
+#undef DECLARE_SUBPARTITION
+#undef DECLARE_SUBPARTITION_0
+#undef FOR_EACH_SUBPARTITION_TABLE
 /** @endcond */
 
 #endif /* USE_PARTITION_MANAGER */
diff --git a/subsys/storage/flash_map/flash_map_default.c b/subsys/storage/flash_map/flash_map_default.c
index c0514d28a12..6b1edfbbaef 100644
--- a/subsys/storage/flash_map/flash_map_default.c
+++ b/subsys/storage/flash_map/flash_map_default.c
@@ -40,6 +40,7 @@
  */
 const struct flash_area default_flash_map[] = {
 	DT_FOREACH_STATUS_OKAY(fixed_partitions, FOREACH_PARTITION)
+	DT_FOREACH_STATUS_OKAY(fixed_subpartitions, FOREACH_PARTITION)
 };
 
 const int flash_map_entries = ARRAY_SIZE(default_flash_map);
@@ -63,11 +64,11 @@ const struct flash_area *flash_map = default_flash_map;
 #define FOR_EACH_PARTITION_TABLE(table) DT_FOREACH_CHILD(table, DEFINE_PARTITION)
 DT_FOREACH_STATUS_OKAY(fixed_partitions, FOR_EACH_PARTITION_TABLE)
 
-#define DEFINE_SUB_PARTITION(part) DEFINE_SUB_PARTITION_1(part, DT_DEP_ORD(part))
-#define DEFINE_SUB_PARTITION_1(part, ord)							\
+#define DEFINE_SUBPARTITION(part) DEFINE_SUBPARTITION_1(part, DT_DEP_ORD(part))
+#define DEFINE_SUBPARTITION_1(part, ord)							\
 	COND_CODE_1(DT_NODE_HAS_STATUS_OKAY(DT_MTD_FROM_FIXED_SUBPARTITION(part)),		\
-		(DEFINE_SUB_PARTITION_0(part, ord)), ())
-#define DEFINE_SUB_PARTITION_0(part, ord)							\
+		(DEFINE_SUBPARTITION_0(part, ord)), ())
+#define DEFINE_SUBPARTITION_0(part, ord)							\
 	const struct flash_area DT_CAT(global_fixed_subpartition_ORD_, ord) = {			\
 		.fa_id = DT_FIXED_PARTITION_ID(part),						\
 		.fa_off = DT_REG_ADDR(part),							\
@@ -75,5 +76,5 @@ DT_FOREACH_STATUS_OKAY(fixed_partitions, FOR_EACH_PARTITION_TABLE)
 		.fa_size = DT_REG_SIZE(part),							\
 	};
 
-#define FOR_EACH_SUB_PARTITION_TABLE(table) DT_FOREACH_CHILD(table, DEFINE_SUB_PARTITION)
-DT_FOREACH_STATUS_OKAY(fixed_subpartitions, FOR_EACH_SUB_PARTITION_TABLE)
+#define FOR_EACH_SUBPARTITION_TABLE(table) DT_FOREACH_CHILD(table, DEFINE_SUBPARTITION)
+DT_FOREACH_STATUS_OKAY(fixed_subpartitions, FOR_EACH_SUBPARTITION_TABLE)
diff --git a/tests/lib/devicetree/api/src/main.c b/tests/lib/devicetree/api/src/main.c
index 98189ebe582..6c154d6dd5e 100644
--- a/tests/lib/devicetree/api/src/main.c
+++ b/tests/lib/devicetree/api/src/main.c
@@ -3271,13 +3271,7 @@ ZTEST(devicetree_api, test_fixed_partitions)
 	/* Test DT_FIXED_PARTITION_ADDR. */
 	zassert_equal(DT_FIXED_PARTITION_ADDR(TEST_PARTITION_0), 0x20000000);
 	zassert_equal(DT_FIXED_PARTITION_ADDR(TEST_PARTITION_1), 0x200000c0);
-
-	/* DT_FIXED_PARTITION_ADDR(TEST_PARTITION_2) expands to an invalid expression.
-	 * Test this by way of string comparison.
-	 */
-	zassert_true(!strcmp(TO_STRING(DT_FIXED_PARTITION_ADDR(TEST_PARTITION_2)),
-			     "(__REG_IDX_0_VAL_ADDRESSU + 458624U)"));
-	zassert_equal(DT_REG_ADDR(TEST_PARTITION_2), 458624);
+	zassert_equal(DT_FIXED_PARTITION_ADDR(TEST_PARTITION_2), 0x33291080);
 
 	/* Test that all DT_FIXED_PARTITION_ID are defined and unique. */
 #define FIXED_PARTITION_ID_COMMA(node_id) DT_FIXED_PARTITION_ID(node_id),
@@ -3312,6 +3306,9 @@ ZTEST(devicetree_api, test_fixed_subpartitions)
 	zassert_true(DT_NODE_EXISTS(DT_MTD_FROM_FIXED_PARTITION(TEST_SUBPARTITION_COMBINED)));
 	zassert_true(DT_NODE_EXISTS(DT_MTD_FROM_FIXED_SUBPARTITION(TEST_SUBPARTITION_0)));
 	zassert_true(DT_NODE_EXISTS(DT_MTD_FROM_FIXED_SUBPARTITION(TEST_SUBPARTITION_1)));
+	zassert_true(DT_SAME_NODE(
+		DT_MTD_FROM_FIXED_PARTITION(TEST_SUBPARTITION_COMBINED),
+		DT_MTD_FROM_FIXED_SUBPARTITION(TEST_SUBPARTITION_1)));
 
 	/* Test DT_FIXED_SUBPARTITION_ADDR. */
 	zassert_equal(DT_FIXED_PARTITION_ADDR(TEST_SUBPARTITION_COMBINED), 0x20000100);