diff --git a/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_ARM_MICRO/M2351.sct b/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_ARM_MICRO/M2351.sct
index d393d81492..e7de211e84 100644
--- a/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_ARM_MICRO/M2351.sct
+++ b/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_ARM_MICRO/M2351.sct
@@ -10,7 +10,7 @@
  *   Secure:        32KiB
  *   Non-secure:    64KiB
  */
-#if defined(__DOMAIN_NS) && __DOMAIN_NS
+#if defined(DOMAIN_NS) && DOMAIN_NS
 
 #ifndef MBED_APP_START
 #define MBED_APP_START      0x10040000
@@ -64,14 +64,14 @@
 
 /* Initial/ISR stack size */
 #if (! defined(NU_INITIAL_STACK_SIZE))
-#if defined(__DOMAIN_NS) && __DOMAIN_NS
+#if defined(DOMAIN_NS) && DOMAIN_NS
 #define NU_INITIAL_STACK_SIZE       0x800
 #else
 #define NU_INITIAL_STACK_SIZE       0x800
 #endif
 #endif
 
-#if defined(__DOMAIN_NS) && __DOMAIN_NS
+#if defined(DOMAIN_NS) && DOMAIN_NS
 
 LR_IROM1    MBED_APP_START
 {
diff --git a/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_ARM_STD/M2351.sct b/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_ARM_STD/M2351.sct
index d393d81492..e7de211e84 100644
--- a/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_ARM_STD/M2351.sct
+++ b/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_ARM_STD/M2351.sct
@@ -10,7 +10,7 @@
  *   Secure:        32KiB
  *   Non-secure:    64KiB
  */
-#if defined(__DOMAIN_NS) && __DOMAIN_NS
+#if defined(DOMAIN_NS) && DOMAIN_NS
 
 #ifndef MBED_APP_START
 #define MBED_APP_START      0x10040000
@@ -64,14 +64,14 @@
 
 /* Initial/ISR stack size */
 #if (! defined(NU_INITIAL_STACK_SIZE))
-#if defined(__DOMAIN_NS) && __DOMAIN_NS
+#if defined(DOMAIN_NS) && DOMAIN_NS
 #define NU_INITIAL_STACK_SIZE       0x800
 #else
 #define NU_INITIAL_STACK_SIZE       0x800
 #endif
 #endif
 
-#if defined(__DOMAIN_NS) && __DOMAIN_NS
+#if defined(DOMAIN_NS) && DOMAIN_NS
 
 LR_IROM1    MBED_APP_START
 {
diff --git a/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_GCC_ARM/M2351.ld b/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_GCC_ARM/M2351.ld
index 956901e5d4..185e5fa42e 100644
--- a/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_GCC_ARM/M2351.ld
+++ b/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_GCC_ARM/M2351.ld
@@ -12,7 +12,7 @@
  *   Secure:        32KiB
  *   Non-secure:    64KiB
  */
-#if defined(__DOMAIN_NS) && __DOMAIN_NS
+#if defined(DOMAIN_NS) && DOMAIN_NS
 
 #ifndef MBED_APP_START
 #define MBED_APP_START      0x10040000
@@ -50,7 +50,7 @@
 
 #endif
 
-#if defined(__DOMAIN_NS) && __DOMAIN_NS
+#if defined(DOMAIN_NS) && DOMAIN_NS
 StackSize = 0x800;
 #else
 StackSize = 0x800;
@@ -71,7 +71,7 @@ StackSize = 0x800;
 #endif
 
 
-#if defined(__DOMAIN_NS) && __DOMAIN_NS
+#if defined(DOMAIN_NS) && DOMAIN_NS
 
 MEMORY
 {
@@ -192,7 +192,7 @@ SECTIONS
         KEEP(*(.eh_frame*))
     } > FLASH
 
-#if (! defined(__DOMAIN_NS)) || (! __DOMAIN_NS)
+#if (! defined(DOMAIN_NS)) || (! DOMAIN_NS)
     /* Veneer$$CMSE : */
     .gnu.sgstubs :
     {
diff --git a/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_IAR/M2351.icf b/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_IAR/M2351.icf
index cc591e7ca7..ab844f73ea 100644
--- a/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_IAR/M2351.icf
+++ b/targets/TARGET_NUVOTON/TARGET_M2351/device/TOOLCHAIN_IAR/M2351.icf
@@ -2,7 +2,7 @@
 /*-Editor annotation file-*/
 /* IcfEditorFile="$TOOLKIT_DIR$\config\ide\IcfEditor\cortex_v1_0.xml" */
 
-if (isdefinedsymbol(__DOMAIN_NS)) {
+if (isdefinedsymbol(DOMAIN_NS)) {
 
     if (! isdefinedsymbol(MBED_APP_START)) {
         define symbol MBED_APP_START                = 0x10040000;
@@ -85,7 +85,7 @@ do not initialize  { section .noinit };
 place at address mem:__ICFEDIT_intvec_start__ { readonly section .intvec };
 
 place in ROM_region   { readonly };
-if (! isdefinedsymbol(__DOMAIN_NS)) {
+if (! isdefinedsymbol(DOMAIN_NS)) {
     place at address mem:__ICFEDIT_region_NSCROM_start__ { readonly section Veneer$$CMSE };
 }
 place at start of IRAM_region   { block CSTACK };
diff --git a/tools/toolchains/arm.py b/tools/toolchains/arm.py
index d37c94e92b..d3614e2c53 100644
--- a/tools/toolchains/arm.py
+++ b/tools/toolchains/arm.py
@@ -424,9 +424,9 @@ class ARMC6(ARM_STD):
             build_dir = kwargs['build_dir']
             secure_file = join(build_dir, "cmse_lib.o")
             self.flags["ld"] += ["--import_cmse_lib_out=%s" % secure_file]
-        # Add linking time preprocessor macro __DOMAIN_NS
+        # Add linking time preprocessor macro DOMAIN_NS
         if target.core == "Cortex-M23-NS" or self.target.core == "Cortex-M33-NS":
-            define_string = self.make_ld_define("__DOMAIN_NS", "0x1")
+            define_string = self.make_ld_define("DOMAIN_NS", "0x1")
             self.flags["ld"].append(define_string)
 
         asm_cpu = {
diff --git a/tools/toolchains/gcc.py b/tools/toolchains/gcc.py
index f094fb9702..5b1a07eb5c 100644
--- a/tools/toolchains/gcc.py
+++ b/tools/toolchains/gcc.py
@@ -97,7 +97,7 @@ class GCC(mbedToolchain):
                 "-Wl,--out-implib=%s" % join(build_dir, "cmse_lib.o")
             ])
         elif target.core == "Cortex-M23-NS" or target.core == "Cortex-M33-NS":
-             self.flags["ld"].append("-D__DOMAIN_NS=1")
+             self.flags["ld"].append("-DDOMAIN_NS=1")
 
         self.flags["common"] += self.cpu