diff --git a/boards/arm/mimxrt1010_evk/mimxrt1010_evk.dts b/boards/arm/mimxrt1010_evk/mimxrt1010_evk.dts
index 5276bc72572..fbca23eac72 100644
--- a/boards/arm/mimxrt1010_evk/mimxrt1010_evk.dts
+++ b/boards/arm/mimxrt1010_evk/mimxrt1010_evk.dts
@@ -43,7 +43,7 @@
 arduino_serial: &lpuart1 {};
 
 &flexspi {
-	reg = <0x402a8000 0x4000>, <0x60000000 0x1000000>;
+	reg = <0x402a8000 0x4000>, <0x60000000 DT_SIZE_M(16)>;
 	at25sf128a: at25sf128a@0 {
 		compatible = "adesto,at25sf128a", "jedec,spi-nor";
 		size = <134217728>;
diff --git a/boards/arm/mimxrt1015_evk/mimxrt1015_evk.dts b/boards/arm/mimxrt1015_evk/mimxrt1015_evk.dts
index d8377ae1612..8716b2bde75 100644
--- a/boards/arm/mimxrt1015_evk/mimxrt1015_evk.dts
+++ b/boards/arm/mimxrt1015_evk/mimxrt1015_evk.dts
@@ -72,7 +72,7 @@
 arduino_serial: &lpuart4 {};
 
 &flexspi {
-	reg = <0x402a8000 0x4000>, <0x60000000 0x1000000>;
+	reg = <0x402a8000 0x4000>, <0x60000000 DT_SIZE_M(16)>;
 	at25sf128a: at25sf128a@0 {
 		compatible = "adesto,at25sf128a", "jedec,spi-nor";
 		size = <134217728>;
diff --git a/boards/arm/mimxrt1020_evk/mimxrt1020_evk.dts b/boards/arm/mimxrt1020_evk/mimxrt1020_evk.dts
index 6c62b9ad307..223ff49824e 100644
--- a/boards/arm/mimxrt1020_evk/mimxrt1020_evk.dts
+++ b/boards/arm/mimxrt1020_evk/mimxrt1020_evk.dts
@@ -27,7 +27,7 @@
 	sdram0: memory@80000000 {
 		/* ISSI IS42S16160J-6TLI */
 		device_type = "memory";
-		reg = <0x80000000 0x2000000>;
+		reg = <0x80000000 DT_SIZE_M(32)>;
 	};
 
 	leds {
@@ -79,7 +79,7 @@
 arduino_serial: &lpuart2 {};
 
 &flexspi {
-	reg = <0x402a8000 0x4000>, <0x60000000 0x800000>;
+	reg = <0x402a8000 0x4000>, <0x60000000 DT_SIZE_M(8)>;
 	is25wp064: is25wp064@0 {
 		compatible = "issi,is25wp064", "jedec,spi-nor";
 		size = <67108864>;
diff --git a/boards/arm/mimxrt1050_evk/mimxrt1050_evk.dts b/boards/arm/mimxrt1050_evk/mimxrt1050_evk.dts
index 05523ccb46e..0a33503d56f 100644
--- a/boards/arm/mimxrt1050_evk/mimxrt1050_evk.dts
+++ b/boards/arm/mimxrt1050_evk/mimxrt1050_evk.dts
@@ -29,7 +29,7 @@
 	sdram0: memory@80000000 {
 		/* Micron MT48LC16M16A2B4-6AIT:G */
 		device_type = "memory";
-		reg = <0x80000000 0x2000000>;
+		reg = <0x80000000 DT_SIZE_M(32)>;
 	};
 
 	leds {
@@ -90,7 +90,7 @@
 arduino_serial: &lpuart3 {};
 
 &flexspi {
-	reg = <0x402a8000 0x4000>, <0x60000000 0x4000000>;
+	reg = <0x402a8000 0x4000>, <0x60000000 DT_SIZE_M(64)>;
 	hyperflash0: hyperflash@0 {
 		compatible = "cypress,s26ks512s";
 		reg = <0>;
diff --git a/boards/arm/mimxrt1050_evk/mimxrt1050_evk_qspi.dts b/boards/arm/mimxrt1050_evk/mimxrt1050_evk_qspi.dts
index c846aa606f2..5b84cfc601c 100644
--- a/boards/arm/mimxrt1050_evk/mimxrt1050_evk_qspi.dts
+++ b/boards/arm/mimxrt1050_evk/mimxrt1050_evk_qspi.dts
@@ -9,7 +9,7 @@
 /delete-node/ &hyperflash0;
 
 &flexspi {
-	reg = <0x402a8000 0x4000>, <0x60000000 0x800000>;
+	reg = <0x402a8000 0x4000>, <0x60000000 DT_SIZE_M(8)>;
 	is25wp064: is25wp064@0 {
 		compatible = "issi,is25wp064", "jedec,spi-nor";
 		size = <67108864>;
diff --git a/boards/arm/mimxrt1060_evk/mimxrt1060_evk.dts b/boards/arm/mimxrt1060_evk/mimxrt1060_evk.dts
index bed08cf5a07..7af897f98d0 100644
--- a/boards/arm/mimxrt1060_evk/mimxrt1060_evk.dts
+++ b/boards/arm/mimxrt1060_evk/mimxrt1060_evk.dts
@@ -30,7 +30,7 @@
 	sdram0: memory@80000000 {
 		/* Micron MT48LC16M16A2B4-6AIT:G */
 		device_type = "memory";
-		reg = <0x80000000 0x2000000>;
+		reg = <0x80000000 DT_SIZE_M(32)>;
 	};
 
 	leds {
@@ -91,7 +91,7 @@
 arduino_serial: &lpuart3 {};
 
 &flexspi {
-	reg = <0x402a8000 0x4000>, <0x60000000 0x800000>;
+	reg = <0x402a8000 0x4000>, <0x60000000 DT_SIZE_M(8)>;
 	is25wp064: is25wp064@0 {
 		compatible = "issi,is25wp064", "jedec,spi-nor";
 		size = <67108864>;
diff --git a/boards/arm/mimxrt1060_evk/mimxrt1060_evk_hyperflash.dts b/boards/arm/mimxrt1060_evk/mimxrt1060_evk_hyperflash.dts
index bea21d50e37..867b34c0710 100644
--- a/boards/arm/mimxrt1060_evk/mimxrt1060_evk_hyperflash.dts
+++ b/boards/arm/mimxrt1060_evk/mimxrt1060_evk_hyperflash.dts
@@ -8,7 +8,7 @@
 
 /delete-node/ &is25wp064;
 &flexspi {
-	reg = <0x402a8000 0x4000>, <0x60000000 0x4000000>;
+	reg = <0x402a8000 0x4000>, <0x60000000 DT_SIZE_M(64)>;
 	hyperflash0: hyperflash@0 {
 		compatible = "cypress,s26ks512s";
 		reg = <0>;
diff --git a/boards/arm/mimxrt1064_evk/mimxrt1064_evk.dts b/boards/arm/mimxrt1064_evk/mimxrt1064_evk.dts
index 80de568a7fd..d1b92c00439 100644
--- a/boards/arm/mimxrt1064_evk/mimxrt1064_evk.dts
+++ b/boards/arm/mimxrt1064_evk/mimxrt1064_evk.dts
@@ -30,7 +30,7 @@
 	sdram0: memory@80000000 {
 		/* Micron MT48LC16M16A2B4-6AIT:G */
 		device_type = "memory";
-		reg = <0x80000000 0x2000000>;
+		reg = <0x80000000 DT_SIZE_M(32)>;
 	};
 
 	leds {
diff --git a/boards/arm/mm_swiftio/mm_swiftio.dts b/boards/arm/mm_swiftio/mm_swiftio.dts
index 23384464d6c..1766cb16af8 100644
--- a/boards/arm/mm_swiftio/mm_swiftio.dts
+++ b/boards/arm/mm_swiftio/mm_swiftio.dts
@@ -28,7 +28,7 @@
 	sdram0: memory@80000000 {
 		/* Micron MT48LC16M16A2B4-6AIT:G */
 		device_type = "memory";
-		reg = <0x80000000 0x2000000>;
+		reg = <0x80000000 DT_SIZE_M(32)>;
 	};
 
 	leds {
@@ -52,7 +52,7 @@
 
 
 &flexspi {
-	reg = <0x402a8000 0x4000>, <0x60000000 0x800000>;
+	reg = <0x402a8000 0x4000>, <0x60000000 DT_SIZE_M(8)>;
 	is25wp064: is25wp064@0 {
 		compatible = "issi,is25wp064", "jedec,spi-nor";
 		size = <67108864>;