diff --git a/ArmPkg/Include/IndustryStandard/ArmTrustZoneSmc.h b/ArmPkg/Include/IndustryStandard/ArmTrustZoneSmc.h
index 62f8f61a7e..71b4327ebf 100644
--- a/ArmPkg/Include/IndustryStandard/ArmTrustZoneSmc.h
+++ b/ArmPkg/Include/IndustryStandard/ArmTrustZoneSmc.h
@@ -18,6 +18,8 @@
 #define ARM_TRUSTZONE_UID_4LETTERID   0x1
 #define ARM_TRUSTZONE_UID_MD5         0x2
 
+#define ARM_TRUSTZONE_ARM_UID         0x40524d48 // "ARMH"
+
 #define IS_ARM_TRUSTZONE_SUPPORTED_SMC(Rx,Region)       (((UINTN)(Rx) >= (UINTN)ARM_TRUSTZONE_##Region##_SMC_ID_START) && ((UINTN)(Rx) <= (UINTN)ARM_TRUSTZONE_##Region##_SMC_ID_END))
 
 #define IS_ARM_TRUSTZONE_DEPRECIATED_SMC(Rx)            ((UINTN)(Rx) <= (UINTN)ARM_TRUSTZONE_DEPRECIATED_SMC_ID_END)
diff --git a/ArmPkg/Library/BdsLib/BdsLinuxFdt.c b/ArmPkg/Library/BdsLib/BdsLinuxFdt.c
index b5dd237136..7bfb2cd628 100644
--- a/ArmPkg/Library/BdsLib/BdsLinuxFdt.c
+++ b/ArmPkg/Library/BdsLib/BdsLinuxFdt.c
@@ -260,8 +260,7 @@ PrepareFdt (
       if (Rx == ARM_TRUSTZONE_UID_4LETTERID) {
         Rx   = ARM_SMC_ID_UID + 1;
         ArmCallSmc (&Rx);
-        //TODO: Replace ARM magic number
-        if (Rx == 0x40524d48) {
+        if (Rx == ARM_TRUSTZONE_ARM_UID) {
           PsciSmcSupported = TRUE;
         }
       }