diff --git a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
index 9377f62..0c0ca61 100644
--- a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
+++ b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
@@ -1037,12 +1037,17 @@
   Get the page base address according to pool head address.
 
   @param[in]  Memory    Head address of pool to free.
+  @param[in]  NoPages   Number of pages actually allocated.
+  @param[in]  Size      Size of memory requested.
+                        (plus pool head/tail overhead)
 
   @return Address of pool head.
 **/
 VOID *
 AdjustPoolHeadF (
-  IN EFI_PHYSICAL_ADDRESS  Memory
+  IN EFI_PHYSICAL_ADDRESS  Memory,
+  IN UINTN                 NoPages,
+  IN UINTN                 Size
   )
 {
   if ((Memory == 0) || ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) != 0)) {
@@ -1053,9 +1058,12 @@
   }
 
   //
-  // Pool head is put near the tail Guard
+  // Pool head is put near the tail Guard. We need to exactly undo the addition done in AdjustPoolHeadA
+  // because we may not have allocated the pool head on the first allocated page, since we are aligned to
+  // the tail and on some architectures, the runtime page allocation granularity is > one page. So we allocate
+  // more pages than we need and put the pool head somewhere past the first page.
   //
-  return (VOID *)(UINTN)(Memory & ~EFI_PAGE_MASK);
+  return (VOID *)(UINTN)(Memory + Size - EFI_PAGES_TO_SIZE (NoPages));
 }
 
 /**
diff --git a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h
index 9a32b4d..24b4206 100644
--- a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h
+++ b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h
@@ -378,12 +378,17 @@
   Get the page base address according to pool head address.
 
   @param[in]  Memory    Head address of pool to free.
+  @param[in]  NoPages   Number of pages actually allocated.
+  @param[in]  Size      Size of memory requested.
+                        (plus pool head/tail overhead)
 
   @return Address of pool head.
 **/
 VOID *
 AdjustPoolHeadF (
-  IN EFI_PHYSICAL_ADDRESS  Memory
+  IN EFI_PHYSICAL_ADDRESS  Memory,
+  IN UINTN                 NoPages,
+  IN UINTN                 Size
   );
 
 /**
diff --git a/MdeModulePkg/Core/Dxe/Mem/Pool.c b/MdeModulePkg/Core/Dxe/Mem/Pool.c
index b20cbfd..716dd04 100644
--- a/MdeModulePkg/Core/Dxe/Mem/Pool.c
+++ b/MdeModulePkg/Core/Dxe/Mem/Pool.c
@@ -783,7 +783,7 @@
     NoPages  = EFI_SIZE_TO_PAGES (Size) + EFI_SIZE_TO_PAGES (Granularity) - 1;
     NoPages &= ~(UINTN)(EFI_SIZE_TO_PAGES (Granularity) - 1);
     if (IsGuarded) {
-      Head = AdjustPoolHeadF ((EFI_PHYSICAL_ADDRESS)(UINTN)Head);
+      Head = AdjustPoolHeadF ((EFI_PHYSICAL_ADDRESS)(UINTN)Head, NoPages, Size);
       CoreFreePoolPagesWithGuard (
         Pool->MemoryType,
         (EFI_PHYSICAL_ADDRESS)(UINTN)Head,