diff --git a/MdePkg/Include/Pi/PiHob.h b/MdePkg/Include/Pi/PiHob.h
index e9f0ab4309..4605da56e2 100644
--- a/MdePkg/Include/Pi/PiHob.h
+++ b/MdePkg/Include/Pi/PiHob.h
@@ -232,7 +232,16 @@ typedef UINT32 EFI_RESOURCE_TYPE;
 #define EFI_RESOURCE_MEMORY_MAPPED_IO_PORT  0x00000004
 #define EFI_RESOURCE_MEMORY_RESERVED        0x00000005
 #define EFI_RESOURCE_IO_RESERVED            0x00000006
-#define EFI_RESOURCE_MAX_MEMORY_TYPE        0x00000007
+//
+// BZ3937_EFI_RESOURCE_MEMORY_UNACCEPTED is defined for unaccepted memory.
+// But this defitinion has not been officially in the PI spec. Base
+// on the code-first we define BZ3937_EFI_RESOURCE_MEMORY_UNACCEPTED at
+// MdeModulePkg/Include/Pi/PrePiHob.h and update EFI_RESOURCE_MAX_MEMORY_TYPE
+// to 8. After BZ3937_EFI_RESOURCE_MEMORY_UNACCEPTED is officially published
+// in PI spec, we will re-visit here.
+//
+// #define BZ3937_EFI_RESOURCE_MEMORY_UNACCEPTED      0x00000007
+#define EFI_RESOURCE_MAX_MEMORY_TYPE  0x00000008
 
 ///
 /// A type of recount attribute type.