diff --git a/ArmPkg/ArmPkg.dec b/ArmPkg/ArmPkg.dec
index 39ff339c95..eaf1072d9e 100644
--- a/ArmPkg/ArmPkg.dec
+++ b/ArmPkg/ArmPkg.dec
@@ -78,10 +78,6 @@
   # Define if the GICv3 controller should use the GICv2 legacy
   gArmTokenSpaceGuid.PcdArmGicV3WithV2Legacy|FALSE|BOOLEAN|0x00000042
 
-  # Whether to implement warm reboot for capsule update using a jump back to the
-  # PEI entry point with caches and interrupts disabled.
-  gArmTokenSpaceGuid.PcdArmReenterPeiForCapsuleWarmReboot|FALSE|BOOLEAN|0x0000001F
-
 [PcdsFeatureFlag.ARM]
   # Whether to map normal memory as non-shareable. FALSE is the safe choice, but
   # TRUE may be appropriate to fix performance problems if you don't care about
diff --git a/ArmPkg/Library/ArmSmcPsciResetSystemLib/AArch64/Reset.S b/ArmPkg/Library/ArmSmcPsciResetSystemLib/AArch64/Reset.S
deleted file mode 100644
index d0d908b7d7..0000000000
--- a/ArmPkg/Library/ArmSmcPsciResetSystemLib/AArch64/Reset.S
+++ /dev/null
@@ -1,24 +0,0 @@
-/** @file
-  ResetSystemLib implementation using PSCI calls
-
-  Copyright (c) 2018, Linaro Ltd. All rights reserved.<BR>
-
-  SPDX-License-Identifier: BSD-2-Clause-Patent
-
-**/
-
-#include <AsmMacroIoLibV8.h>
-
-ASM_FUNC(DisableMmuAndReenterPei)
-  stp   x29, x30, [sp, #-16]!
-  mov   x29, sp
-
-  bl    ArmDisableMmu
-
-  // no memory accesses after MMU and caches have been disabled
-
-  MOV64 (x0, FixedPcdGet64 (PcdFvBaseAddress))
-  blr   x0
-
-  // never returns
-  nop
diff --git a/ArmPkg/Library/ArmSmcPsciResetSystemLib/AArch64/Reset.asm b/ArmPkg/Library/ArmSmcPsciResetSystemLib/AArch64/Reset.asm
deleted file mode 100644
index 752df07251..0000000000
--- a/ArmPkg/Library/ArmSmcPsciResetSystemLib/AArch64/Reset.asm
+++ /dev/null
@@ -1,29 +0,0 @@
-;/** @file
-;  ResetSystemLib implementation using PSCI calls
-;
-;  Copyright (c) 2018, Linaro Ltd. All rights reserved.<BR>
-;
-;  SPDX-License-Identifier: BSD-2-Clause-Patent
-;
-;**/
-
-  AREA Reset, CODE, READONLY
-
-  EXPORT DisableMmuAndReenterPei
-  IMPORT ArmDisableMmu
-
-DisableMmuAndReenterPei
-  stp   x29, x30, [sp, #-16]!
-  mov   x29, sp
-
-  bl    ArmDisableMmu
-
-  ; no memory accesses after MMU and caches have been disabled
-
-  movl  x0, FixedPcdGet64 (PcdFvBaseAddress)
-  blr   x0
-
-  ; never returns
-  nop
-
-  END
diff --git a/ArmPkg/Library/ArmSmcPsciResetSystemLib/Arm/Reset.S b/ArmPkg/Library/ArmSmcPsciResetSystemLib/Arm/Reset.S
deleted file mode 100644
index c0c5bcf197..0000000000
--- a/ArmPkg/Library/ArmSmcPsciResetSystemLib/Arm/Reset.S
+++ /dev/null
@@ -1,23 +0,0 @@
-/** @file
-  ResetSystemLib implementation using PSCI calls
-
-  Copyright (c) 2018, Linaro Ltd. All rights reserved.<BR>
-
-  SPDX-License-Identifier: BSD-2-Clause-Patent
-
-**/
-
-#include <AsmMacroIoLib.h>
-
-ASM_FUNC(DisableMmuAndReenterPei)
-  push  {lr}
-
-  bl    ArmDisableMmu
-
-  // no memory accesses after MMU and caches have been disabled
-
-  MOV32 (r0, FixedPcdGet64 (PcdFvBaseAddress))
-  blx   r0
-
-  // never returns
-  nop
diff --git a/ArmPkg/Library/ArmSmcPsciResetSystemLib/Arm/Reset.asm b/ArmPkg/Library/ArmSmcPsciResetSystemLib/Arm/Reset.asm
deleted file mode 100644
index ab7519a5a9..0000000000
--- a/ArmPkg/Library/ArmSmcPsciResetSystemLib/Arm/Reset.asm
+++ /dev/null
@@ -1,28 +0,0 @@
-;/** @file
-;  ResetSystemLib implementation using PSCI calls
-;
-;  Copyright (c) 2018, Linaro Ltd. All rights reserved.<BR>
-;
-;  SPDX-License-Identifier: BSD-2-Clause-Patent
-;
-;**/
-
-  INCLUDE AsmMacroExport.inc
-  PRESERVE8
-
-  IMPORT ArmDisableMmu
-
-RVCT_ASM_EXPORT DisableMmuAndReenterPei
-  push  {lr}
-
-  bl    ArmDisableMmu
-
-  ; no memory accesses after MMU and caches have been disabled
-
-  mov32 r0, FixedPcdGet64 (PcdFvBaseAddress)
-  blx   r0
-
-  ; never returns
-  nop
-
-  END
diff --git a/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c b/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
index b2dde9bfc1..8b5ff5c27e 100644
--- a/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
+++ b/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
@@ -10,13 +10,10 @@
 
 #include <PiDxe.h>
 
-#include <Library/ArmMmuLib.h>
 #include <Library/ArmSmcLib.h>
 #include <Library/BaseLib.h>
 #include <Library/DebugLib.h>
 #include <Library/ResetSystemLib.h>
-#include <Library/UefiBootServicesTableLib.h>
-#include <Library/UefiRuntimeLib.h>
 
 #include <IndustryStandard/ArmStdSmc.h>
 
@@ -76,79 +73,6 @@ ResetShutdown (
   ArmCallSmc (&ArmSmcArgs);
 }
 
-VOID DisableMmuAndReenterPei (VOID);
-
-/**
-  This function causes the system to enter S3 and then wake up immediately.
-
-  If this function returns, it means that the system does not support S3 feature.
-**/
-VOID
-EFIAPI
-EnterS3WithImmediateWake (
-  VOID
-  )
-{
-  EFI_PHYSICAL_ADDRESS        Alloc;
-  EFI_MEMORY_DESCRIPTOR       *MemMap;
-  UINTN                       MemMapSize;
-  UINTN                       MapKey, DescriptorSize;
-  UINT32                      DescriptorVersion;
-  EFI_STATUS                  Status;
-
-  if (FeaturePcdGet (PcdArmReenterPeiForCapsuleWarmReboot) &&
-      !EfiAtRuntime ()) {
-    //
-    // At boot time, we are the only core running, so we can implement the
-    // immediate wake (which is used by capsule update) by disabling the MMU
-    // and interrupts, and jumping to the PEI entry point.
-    //
-
-    //
-    // Obtain the size of the memory map
-    //
-    MemMapSize = 0;
-    MemMap = NULL;
-    Status = gBS->GetMemoryMap (&MemMapSize, MemMap, &MapKey, &DescriptorSize,
-                    &DescriptorVersion);
-    ASSERT (Status == EFI_BUFFER_TOO_SMALL);
-
-    //
-    // Add some slack to the allocation to cater for changes in the memory
-    // map if ExitBootServices () fails the first time around.
-    //
-    MemMapSize += SIZE_4KB;
-    Status = gBS->AllocatePages (AllocateAnyPages, EfiBootServicesData,
-                    EFI_SIZE_TO_PAGES (MemMapSize), &Alloc);
-    ASSERT_EFI_ERROR (Status);
-
-    MemMap = (EFI_MEMORY_DESCRIPTOR *)(UINTN)Alloc;
-
-    Status = gBS->GetMemoryMap (&MemMapSize, MemMap, &MapKey, &DescriptorSize,
-                    &DescriptorVersion);
-    ASSERT_EFI_ERROR (Status);
-
-    Status = gBS->ExitBootServices (gImageHandle, MapKey);
-    if (EFI_ERROR (Status)) {
-      //
-      // ExitBootServices () may fail the first time around if an event fired
-      // right after the call to GetMemoryMap() which allocated or freed memory.
-      // Since that first call to ExitBootServices () will disarm the timer,
-      // this is guaranteed not to happen again, so one additional attempt
-      // should suffice.
-      //
-      Status = gBS->GetMemoryMap (&MemMapSize, MemMap, &MapKey, &DescriptorSize,
-                      &DescriptorVersion);
-      ASSERT_EFI_ERROR (Status);
-
-      Status = gBS->ExitBootServices (gImageHandle, MapKey);
-      ASSERT_EFI_ERROR (Status);
-    }
-
-    DisableMmuAndReenterPei ();
-  }
-}
-
 /**
   This function causes a systemwide reset. The exact type of the reset is
   defined by the EFI_GUID that follows the Null-terminated Unicode string passed
diff --git a/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.inf b/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.inf
index fa19bf6491..c17b28cfac 100644
--- a/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.inf
+++ b/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.inf
@@ -15,14 +15,6 @@
   VERSION_STRING                 = 1.0
   LIBRARY_CLASS                  = ResetSystemLib
 
-[Sources.AARCH64]
-  AArch64/Reset.S   | GCC
-  AArch64/Reset.asm | MSFT
-
-[Sources.ARM]
-  Arm/Reset.S       | GCC
-  Arm/Reset.asm     | RVCT
-
 [Sources]
   ArmSmcPsciResetSystemLib.c
 
@@ -32,15 +24,6 @@
   MdePkg/MdePkg.dec
 
 [LibraryClasses]
-  ArmMmuLib
   ArmSmcLib
   BaseLib
   DebugLib
-  UefiBootServicesTableLib
-  UefiRuntimeLib
-
-[FeaturePcd]
-  gArmTokenSpaceGuid.PcdArmReenterPeiForCapsuleWarmReboot
-
-[FixedPcd]
-  gArmTokenSpaceGuid.PcdFvBaseAddress