diff --git a/EdkModulePkg/Include/Protocol/UgaIo.h b/EdkModulePkg/Include/Protocol/UgaIo.h
index 91ff8df35a..561dafd098 100644
--- a/EdkModulePkg/Include/Protocol/UgaIo.h
+++ b/EdkModulePkg/Include/Protocol/UgaIo.h
@@ -63,7 +63,6 @@ typedef struct _UGA_DEVICE {
 }
 UGA_DEVICE, *PUGA_DEVICE;
 
-#ifndef UGA_IO_REQUEST_CODE
 //
 // Prevent conflicts with UGA typedefs.
 //
@@ -94,8 +93,6 @@ typedef enum {
 }
 UGA_IO_REQUEST_CODE, *PUGA_IO_REQUEST_CODE;
 
-#endif
-
 typedef struct {
   IN UGA_IO_REQUEST_CODE  ioRequestCode;
   IN VOID                 *pvInBuffer;
diff --git a/EdkModulePkg/Library/EdkGenericPlatformBdsLib/BootMaint/BootMaint.h b/EdkModulePkg/Library/EdkGenericPlatformBdsLib/BootMaint/BootMaint.h
index 6c3489f269..a5c9f0d920 100644
--- a/EdkModulePkg/Library/EdkGenericPlatformBdsLib/BootMaint/BootMaint.h
+++ b/EdkModulePkg/Library/EdkGenericPlatformBdsLib/BootMaint/BootMaint.h
@@ -85,16 +85,14 @@ Revision History
 // Check to see if current build support option active feature of
 // some driver option
 //
-#ifndef LOAD_OPTION_ACTIVE
 #define LOAD_OPTION_ACTIVE  0x00000001
-#endif
+
 //
 // Check to see if current build support force reconnect feature of
 // some driver option
 //
-#ifndef LOAD_OPTION_FORCE_RECONNECT
 #define LOAD_OPTION_FORCE_RECONNECT 0x00000002
-#endif
+
 //
 // Below are the form ids for display, form id is used as callback key value,
 // some key value definitions are also defined here. By defining this enum type,
diff --git a/EdkModulePkg/Library/EdkGenericPlatformBdsLib/Language.h b/EdkModulePkg/Library/EdkGenericPlatformBdsLib/Language.h
index 6b6d887040..a7c32ece0e 100644
--- a/EdkModulePkg/Library/EdkGenericPlatformBdsLib/Language.h
+++ b/EdkModulePkg/Library/EdkGenericPlatformBdsLib/Language.h
@@ -24,9 +24,7 @@ Revision History
 #ifndef _LANGUAGE_H
 #define _LANGUAGE_H
 
-#ifndef ISO_639_2_ENTRY_SIZE
 #define ISO_639_2_ENTRY_SIZE  3
-#endif
 
 VOID
 InitializeLanguage (
diff --git a/EdkNt32Pkg/Dxe/PlatformBds/Generic/BootMaint/BootMaint.h b/EdkNt32Pkg/Dxe/PlatformBds/Generic/BootMaint/BootMaint.h
index d2a3e3d30e..13fd28140e 100644
--- a/EdkNt32Pkg/Dxe/PlatformBds/Generic/BootMaint/BootMaint.h
+++ b/EdkNt32Pkg/Dxe/PlatformBds/Generic/BootMaint/BootMaint.h
@@ -85,16 +85,14 @@ Revision History
 // Check to see if current build support option active feature of
 // some driver option
 //
-#ifndef LOAD_OPTION_ACTIVE
 #define LOAD_OPTION_ACTIVE  0x00000001
-#endif
+
 //
 // Check to see if current build support force reconnect feature of
 // some driver option
 //
-#ifndef LOAD_OPTION_FORCE_RECONNECT
 #define LOAD_OPTION_FORCE_RECONNECT 0x00000002
-#endif
+
 //
 // Below are the form ids for display, form id is used as callback key value,
 // some key value definitions are also defined here. By defining this enum type,
diff --git a/EdkNt32Pkg/Dxe/PlatformBds/Generic/Language.h b/EdkNt32Pkg/Dxe/PlatformBds/Generic/Language.h
index 6b6d887040..a7c32ece0e 100644
--- a/EdkNt32Pkg/Dxe/PlatformBds/Generic/Language.h
+++ b/EdkNt32Pkg/Dxe/PlatformBds/Generic/Language.h
@@ -24,9 +24,7 @@ Revision History
 #ifndef _LANGUAGE_H
 #define _LANGUAGE_H
 
-#ifndef ISO_639_2_ENTRY_SIZE
 #define ISO_639_2_ENTRY_SIZE  3
-#endif
 
 VOID
 InitializeLanguage (
diff --git a/MdePkg/Include/Protocol/IP4.h b/MdePkg/Include/Protocol/IP4.h
index 5a6ab5976b..571c534a5a 100644
--- a/MdePkg/Include/Protocol/IP4.h
+++ b/MdePkg/Include/Protocol/IP4.h
@@ -83,13 +83,8 @@ typedef struct {
 #pragma pack(1)
 
 typedef struct {
-#ifdef EFI_NET_LITTLE_ENDIAN
   UINT8                   HeaderLength:4;
   UINT8                   Version:4;
-#else 
-  UINT8                   Version:4;
-  UINT8                   HeaderLength:4;
-#endif
   UINT8                   TypeOfService;
   UINT16                  TotalLength;
   UINT16                  Identification;