diff --git a/MdePkg/Library/BaseLib/Ia32/Thunk16.asm b/MdePkg/Library/BaseLib/Ia32/Thunk16.asm
index 454b8905bc..9a78766027 100644
--- a/MdePkg/Library/BaseLib/Ia32/Thunk16.asm
+++ b/MdePkg/Library/BaseLib/Ia32/Thunk16.asm
@@ -29,9 +29,9 @@ EXTERNDEF   C   m16Gdt:WORD
 EXTERNDEF   C   m16GdtrBase:WORD
 EXTERNDEF   C   mTransition:WORD
 
-THUNK_ATTRIBUTE_BIG_REAL_MODE               EQU 1
-THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15     EQU 2
-THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL   EQU 4
+;THUNK_ATTRIBUTE_BIG_REAL_MODE               EQU 1
+;THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15     EQU 2
+;THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL   EQU 4
 
 IA32_REGS   STRUC   4t
 _EDI        DD      ?
diff --git a/MdePkg/Library/BaseLib/X64/Thunk16.asm b/MdePkg/Library/BaseLib/X64/Thunk16.asm
index 23450ed81b..b3c0769f1f 100644
--- a/MdePkg/Library/BaseLib/X64/Thunk16.asm
+++ b/MdePkg/Library/BaseLib/X64/Thunk16.asm
@@ -26,8 +26,8 @@ EXTERNDEF   m16Gdt:WORD
 EXTERNDEF   m16GdtrBase:WORD
 EXTERNDEF   mTransition:WORD
 
-THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15     EQU 2
-THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL   EQU 4
+;THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15     EQU 2
+;THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL   EQU 4
 
 IA32_REGS   STRUC   4t
 _EDI        DD      ?