diff --git a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
index b83373d4b5..64386aac1e 100644
--- a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
+++ b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
@@ -568,6 +568,11 @@ ArmConfigureMmu (
   UINT64      TCR;
   EFI_STATUS  Status;
 
+  ASSERT (ArmReadCurrentEL () < AARCH64_EL3);
+  if (ArmReadCurrentEL () == AARCH64_EL3) {
+    return EFI_UNSUPPORTED;
+  }
+
   if (MemoryTable == NULL) {
     ASSERT (MemoryTable != NULL);
     return EFI_INVALID_PARAMETER;
@@ -617,7 +622,7 @@ ArmConfigureMmu (
       ASSERT (0); // Bigger than 48-bit memory space are not supported
       return EFI_UNSUPPORTED;
     }
-  } else if (ArmReadCurrentEL () == AARCH64_EL1) {
+  } else {
     // Due to Cortex-A57 erratum #822227 we must set TG1[1] == 1, regardless of EPD1.
     TCR = T0SZ | TCR_TG0_4KB | TCR_TG1_4KB | TCR_EPD1;
 
@@ -643,9 +648,6 @@ ArmConfigureMmu (
       ASSERT (0); // Bigger than 48-bit memory space are not supported
       return EFI_UNSUPPORTED;
     }
-  } else {
-    ASSERT (0); // UEFI is only expected to run at EL2 and EL1, not EL3.
-    return EFI_UNSUPPORTED;
   }
 
   //