diff --git a/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.c b/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.c
index 4483aaef99..496cf21396 100644
--- a/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.c
+++ b/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.c
@@ -454,7 +454,10 @@ CreatMmHobList (
                         MmProfileDataHob,
                         Block
                         );
-  FreePages (PlatformHobList, EFI_SIZE_TO_PAGES (PlatformHobSize));
+  if (PlatformHobSize != 0) {
+    FreePages (PlatformHobList, EFI_SIZE_TO_PAGES (PlatformHobSize));
+  }
+
   ASSERT (Status == RETURN_BUFFER_TOO_SMALL);
   ASSERT (FoundationHobSize != 0);
 
@@ -652,6 +655,7 @@ ExecuteMmCoreFromMmram (
   )
 {
   EFI_STATUS                            Status;
+  EFI_STATUS                            AccessStatus; // MU_CHANGE: Separate variable to avoid overwriting Status
   UINTN                                 PageCount;
   VOID                                  *MmHobList;
   UINTN                                 MmHobSize;
@@ -661,6 +665,10 @@ ExecuteMmCoreFromMmram (
   PE_COFF_LOADER_IMAGE_CONTEXT          ImageContext;
   STANDALONE_MM_FOUNDATION_ENTRY_POINT  Entry;
   EFI_MMRAM_HOB_DESCRIPTOR_BLOCK        *Block;
+  EFI_PEI_MM_ACCESS_PPI                 *MmAccess;
+  UINTN                                 Size;
+  UINTN                                 Index;
+  UINTN                                 MmramRangeCount;
 
   MmFvBase = 0;
   MmFvSize = 0;
@@ -670,6 +678,40 @@ ExecuteMmCoreFromMmram (
   Status = LocateMmCoreFv (&MmFvBase, &MmFvSize, &MmCoreFileName, &ImageContext.Handle);
   ASSERT_EFI_ERROR (Status);
 
+  //
+  // Prepare an MM access PPI for MM RAM.
+  //
+  MmAccess        = NULL;
+  MmramRangeCount = 0;
+  Status          = PeiServicesLocatePpi (
+                      &gEfiPeiMmAccessPpiGuid,
+                      0,
+                      NULL,
+                      (VOID **)&MmAccess
+                      );
+  if (!EFI_ERROR (Status)) {
+    //
+    // Open all MMRAM ranges, if MmAccess is available.
+    //
+    Size   = 0;
+    Status = MmAccess->GetCapabilities ((EFI_PEI_SERVICES **)GetPeiServicesTablePointer (), MmAccess, &Size, NULL);
+    if (Status != EFI_BUFFER_TOO_SMALL) {
+      // This is not right...
+      ASSERT (Status == EFI_BUFFER_TOO_SMALL);
+      return EFI_DEVICE_ERROR;
+    }
+
+    MmramRangeCount = Size / sizeof (EFI_MMRAM_DESCRIPTOR);
+    for (Index = 0; Index < MmramRangeCount; Index++) {
+      Status = MmAccess->Open ((EFI_PEI_SERVICES **)GetPeiServicesTablePointer (), MmAccess, Index);
+      if (EFI_ERROR (Status)) {
+        DEBUG ((DEBUG_ERROR, "MM IPL failed to open MMRAM windows index %d - %r\n", Index, Status));
+        ASSERT_EFI_ERROR (Status);
+        goto Done;
+      }
+    }
+  }
+
   //
   // Initialize ImageContext
   //
@@ -680,7 +722,7 @@ ExecuteMmCoreFromMmram (
   //
   Status = PeCoffLoaderGetImageInfo (&ImageContext);
   if (EFI_ERROR (Status)) {
-    return Status;
+    goto Done;
   }
 
   PageCount = (UINTN)EFI_SIZE_TO_PAGES ((UINTN)ImageContext.ImageSize + ImageContext.SectionAlignment);
@@ -690,7 +732,8 @@ ExecuteMmCoreFromMmram (
   //
   ImageContext.ImageAddress = MmIplAllocateMmramPage (PageCount, &Block);
   if (ImageContext.ImageAddress == 0) {
-    return EFI_NOT_FOUND;
+    Status = EFI_NOT_FOUND;
+    goto Done;
   }
 
   //
@@ -753,6 +796,48 @@ ExecuteMmCoreFromMmram (
     }
   }
 
+Done:
+  if (MmAccess != NULL) {
+    //
+    // Close all MMRAM ranges, if MmAccess is available.
+    //
+    for (Index = 0; Index < MmramRangeCount; Index++) {
+      // MU_CHANGE START: Will not return if error occurs
+      AccessStatus = MmAccess->Close ((EFI_PEI_SERVICES **)GetPeiServicesTablePointer (), MmAccess, Index);
+      if (EFI_ERROR (AccessStatus)) {
+        DEBUG ((DEBUG_ERROR, "MM IPL failed to close MMRAM windows index %d - %r\n", Index, AccessStatus));
+        ASSERT (FALSE);
+      }
+
+      // MU_CHANGE END: Will not return if error occurs
+
+      //
+      // Print debug message that the MMRAM window is now closed.
+      //
+      DEBUG ((DEBUG_INFO, "MM IPL closed MMRAM window index %d\n", Index));
+
+      //
+      // Lock the MMRAM (Note: Locking MMRAM may not be supported on all platforms)
+      //
+      // MU_CHANGE START: Will not return if error occurs and allow UNSUPPORTED
+      AccessStatus = MmAccess->Lock ((EFI_PEI_SERVICES **)GetPeiServicesTablePointer (), MmAccess, Index);
+      if (EFI_ERROR (AccessStatus) && (AccessStatus != EFI_UNSUPPORTED)) {
+        //
+        // Print error message that the MMRAM failed to lock...
+        //
+        DEBUG ((DEBUG_ERROR, "MM IPL could not lock MMRAM (Index %d) after executing MM Core %r\n", Index, AccessStatus));
+        ASSERT (FALSE);
+      }
+
+      // MU_CHANGE END: Will not return if error occurs and allow UNSUPPORTED
+
+      //
+      // Print debug message that the MMRAM window is now locked.
+      //
+      DEBUG ((DEBUG_INFO, "MM IPL locked MMRAM window index %d\n", Index));
+    }
+  }
+
   return Status;
 }
 
diff --git a/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.h b/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.h
index 1f3b49e6a7..35861133e7 100644
--- a/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.h
+++ b/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.h
@@ -21,6 +21,7 @@
 #include <Library/PeCoffLib.h>
 #include <Library/CacheMaintenanceLib.h>
 #include <Library/PeiServicesTablePointerLib.h>
+#include <Ppi/MmAccess.h>
 #include <Ppi/MmControl.h>
 #include <Ppi/MmCommunication.h>
 #include <Ppi/MmCommunication3.h>
diff --git a/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.inf b/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.inf
index 84781d6c59..09908bdeaf 100644
--- a/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.inf
+++ b/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.inf
@@ -65,6 +65,7 @@
   gEfiPeiMmCommunication3PpiGuid
   gEfiEndOfPeiSignalPpiGuid
   gMmCoreFvLocationPpiGuid
+  gEfiPeiMmAccessPpiGuid
 
 [Protocols]
   gEfiMmEndOfPeiProtocol