diff --git a/MdeModulePkg/Core/Dxe/Gcd/Gcd.c b/MdeModulePkg/Core/Dxe/Gcd/Gcd.c
index c450d1bf25..fe1bbd6974 100644
--- a/MdeModulePkg/Core/Dxe/Gcd/Gcd.c
+++ b/MdeModulePkg/Core/Dxe/Gcd/Gcd.c
@@ -8,8 +8,8 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
 
-#include <Pi/PrePiDxeCis.h>
-#include <Pi/PrePiHob.h>
+#include <Pi/PiDxeCis.h>
+#include <Pi/PiHob.h>
 #include "DxeMain.h"
 #include "Gcd.h"
 #include "Mem/HeapGuard.h"
@@ -105,7 +105,7 @@ GLOBAL_REMOVE_IF_UNREFERENCED CONST CHAR8  *mGcdMemoryTypeNames[] = {
   "MMIO     ",  // EfiGcdMemoryTypeMemoryMappedIo
   "PersisMem",  // EfiGcdMemoryTypePersistent
   "MoreRelia",  // EfiGcdMemoryTypeMoreReliable
-  "Unaccepte",  // EFI_GCD_MEMORY_TYPE_UNACCEPTED
+  "Unaccepte",  // EfiGcdMemoryTypeUnaccepted
   "Unknown  "   // EfiGcdMemoryTypeMaximum
 };
 
@@ -2669,8 +2669,8 @@ CoreInitializeGcdServices (
         case EFI_RESOURCE_MEMORY_RESERVED:
           GcdMemoryType = EfiGcdMemoryTypeReserved;
           break;
-        case BZ3937_EFI_RESOURCE_MEMORY_UNACCEPTED:
-          GcdMemoryType = EFI_GCD_MEMORY_TYPE_UNACCEPTED;
+        case EFI_RESOURCE_MEMORY_UNACCEPTED:
+          GcdMemoryType = EfiGcdMemoryTypeUnaccepted;
           break;
         case EFI_RESOURCE_IO:
           GcdIoType = EfiGcdIoTypeIo;
diff --git a/MdeModulePkg/Core/Dxe/Mem/Page.c b/MdeModulePkg/Core/Dxe/Mem/Page.c
index 26584648c2..5a51d9df1a 100644
--- a/MdeModulePkg/Core/Dxe/Mem/Page.c
+++ b/MdeModulePkg/Core/Dxe/Mem/Page.c
@@ -9,7 +9,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 #include "DxeMain.h"
 #include "Imem.h"
 #include "HeapGuard.h"
-#include <Pi/PrePiDxeCis.h>
+#include <Pi/PiDxeCis.h>
 
 //
 // Entry for tracking the memory regions for each memory type to coalesce similar memory types
@@ -70,23 +70,23 @@ EFI_PHYSICAL_ADDRESS  mDefaultMaximumAddress = MAX_ALLOC_ADDRESS;
 EFI_PHYSICAL_ADDRESS  mDefaultBaseAddress    = MAX_ALLOC_ADDRESS;
 
 EFI_MEMORY_TYPE_INFORMATION  gMemoryTypeInformation[EfiMaxMemoryType + 1] = {
-  { EfiReservedMemoryType,          0 },
-  { EfiLoaderCode,                  0 },
-  { EfiLoaderData,                  0 },
-  { EfiBootServicesCode,            0 },
-  { EfiBootServicesData,            0 },
-  { EfiRuntimeServicesCode,         0 },
-  { EfiRuntimeServicesData,         0 },
-  { EfiConventionalMemory,          0 },
-  { EfiUnusableMemory,              0 },
-  { EfiACPIReclaimMemory,           0 },
-  { EfiACPIMemoryNVS,               0 },
-  { EfiMemoryMappedIO,              0 },
-  { EfiMemoryMappedIOPortSpace,     0 },
-  { EfiPalCode,                     0 },
-  { EfiPersistentMemory,            0 },
-  { EFI_GCD_MEMORY_TYPE_UNACCEPTED, 0 },
-  { EfiMaxMemoryType,               0 }
+  { EfiReservedMemoryType,      0 },
+  { EfiLoaderCode,              0 },
+  { EfiLoaderData,              0 },
+  { EfiBootServicesCode,        0 },
+  { EfiBootServicesData,        0 },
+  { EfiRuntimeServicesCode,     0 },
+  { EfiRuntimeServicesData,     0 },
+  { EfiConventionalMemory,      0 },
+  { EfiUnusableMemory,          0 },
+  { EfiACPIReclaimMemory,       0 },
+  { EfiACPIMemoryNVS,           0 },
+  { EfiMemoryMappedIO,          0 },
+  { EfiMemoryMappedIOPortSpace, 0 },
+  { EfiPalCode,                 0 },
+  { EfiPersistentMemory,        0 },
+  { EfiGcdMemoryTypeUnaccepted, 0 },
+  { EfiMaxMemoryType,           0 }
 };
 //
 // Only used when load module at fixed address feature is enabled. True means the memory is alreay successfully allocated
@@ -2083,7 +2083,7 @@ CoreGetMemoryMap (
       MemoryMap = MergeMemoryMapDescriptor (MemoryMapStart, MemoryMap, Size);
     }
 
-    if (MergeGcdMapEntry.GcdMemoryType == EFI_GCD_MEMORY_TYPE_UNACCEPTED) {
+    if (MergeGcdMapEntry.GcdMemoryType == EfiGcdMemoryTypeUnaccepted) {
       //
       // Page Align GCD range is required. When it is converted to EFI_MEMORY_DESCRIPTOR,
       // it will be recorded as page PhysicalStart and NumberOfPages.
diff --git a/MdeModulePkg/Include/Pi/PrePiDxeCis.h b/MdeModulePkg/Include/Pi/PrePiDxeCis.h
deleted file mode 100644
index 9be71d2618..0000000000
--- a/MdeModulePkg/Include/Pi/PrePiDxeCis.h
+++ /dev/null
@@ -1,25 +0,0 @@
-/** @file
-  Include file matches things in PI.
-
-Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
-SPDX-License-Identifier: BSD-2-Clause-Patent
-
-**/
-
-#ifndef MDE_MODULEPKG_PRE_PI_DXE_CIS_H_
-#define MDE_MODULEPKG_PRE_PI_DXE_CIS_H_
-
-///
-/// A memory region that describes system memory that has not been accepted
-/// by a corresponding call to the underlying isolation architecture.
-///
-/// This memory region has not been defined in PI spec, so it is defined in
-/// PrePiDxeCis.h. And it is defined in the format of captial letters
-/// because only capital letters are allowed to be used for #define declarations.
-///
-/// After this memory region is defined in PI spec, it should be a value in
-/// EFI_GCD_MEMORY_TYPE in PiDxeCis.h.
-///
-#define  EFI_GCD_MEMORY_TYPE_UNACCEPTED  6
-
-#endif
diff --git a/MdeModulePkg/Include/Pi/PrePiHob.h b/MdeModulePkg/Include/Pi/PrePiHob.h
deleted file mode 100644
index ac575e5972..0000000000
--- a/MdeModulePkg/Include/Pi/PrePiHob.h
+++ /dev/null
@@ -1,20 +0,0 @@
-/** @file
-  HOB related definitions which has not been officially published in PI.
-
-Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
-SPDX-License-Identifier: BSD-2-Clause-Patent
-
-**/
-
-#ifndef MDE_MODULEPKG_PRE_PI_HOB_H_
-#define MDE_MODULEPKG_PRE_PI_HOB_H_
-
-//
-// 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.
-//
-#define BZ3937_EFI_RESOURCE_MEMORY_UNACCEPTED  0x00000007
-
-#endif