diff --git a/ArmPkg/Include/Library/ArmLib.h b/ArmPkg/Include/Library/ArmLib.h
index 24ffe9f1aa..24e84c7a19 100644
--- a/ArmPkg/Include/Library/ArmLib.h
+++ b/ArmPkg/Include/Library/ArmLib.h
@@ -41,6 +41,14 @@ typedef enum {
   ARM_MEMORY_REGION_ATTRIBUTE_NONSECURE_UNCACHED_UNBUFFERED,
   ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK,
   ARM_MEMORY_REGION_ATTRIBUTE_NONSECURE_WRITE_BACK,
+
+  // On some platforms, memory mapped flash region is designed as not supporting
+  // shareable attribute, so WRITE_BACK_NONSHAREABLE is added for such special
+  // need.
+  // Do NOT use below two attributes if you are not sure.
+  ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_NONSHAREABLE,
+  ARM_MEMORY_REGION_ATTRIBUTE_NONSECURE_WRITE_BACK_NONSHAREABLE,
+
   ARM_MEMORY_REGION_ATTRIBUTE_WRITE_THROUGH,
   ARM_MEMORY_REGION_ATTRIBUTE_NONSECURE_WRITE_THROUGH,
   ARM_MEMORY_REGION_ATTRIBUTE_DEVICE,
diff --git a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
index 8bd1c6fad9..4b62ecb6a4 100644
--- a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
+++ b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
@@ -35,6 +35,10 @@ ArmMemoryAttributeToPageAttribute (
   )
 {
   switch (Attributes) {
+  case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK_NONSHAREABLE:
+  case ARM_MEMORY_REGION_ATTRIBUTE_NONSECURE_WRITE_BACK_NONSHAREABLE:
+    return TT_ATTR_INDX_MEMORY_WRITE_BACK;
+
   case ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK:
   case ARM_MEMORY_REGION_ATTRIBUTE_NONSECURE_WRITE_BACK:
     return TT_ATTR_INDX_MEMORY_WRITE_BACK | TT_SH_INNER_SHAREABLE;