diff --git a/BOOT/ENVIRON/INC/mm.h b/BOOT/ENVIRON/INC/mm.h
index a175de7..1b77c9a 100644
--- a/BOOT/ENVIRON/INC/mm.h
+++ b/BOOT/ENVIRON/INC/mm.h
@@ -53,6 +53,13 @@ MmMdRemoveDescriptorFromList (
     IN PMEMORY_DESCRIPTOR Descriptor
     );
 
+PMEMORY_DESCRIPTOR
+MmMdFindDescriptorFromMdl (
+    IN PMEMORY_DESCRIPTOR_LIST Mdl,
+    IN ULONGLONG Page,
+    IN ULONG Flags
+    );
+
 NTSTATUS
 MmMdRemoveRegionFromMdlEx (
     IN PMEMORY_DESCRIPTOR_LIST Mdl,
diff --git a/BOOT/ENVIRON/LIB/EFI/efimm.c b/BOOT/ENVIRON/LIB/EFI/efimm.c
index b4e033d..3bec1aa 100644
--- a/BOOT/ENVIRON/LIB/EFI/efimm.c
+++ b/BOOT/ENVIRON/LIB/EFI/efimm.c
@@ -302,17 +302,18 @@ Return Value:
 
 {
     NTSTATUS Status;
-    UINTN EfiMapSize;
-    UINTN EfiMapKey;
-    UINTN EfiDescriptorSize;
-    UINT32 EfiDescriptorVersion;
-    UINTN PageCount, EfiPageCount;
     EFI_PHYSICAL_ADDRESS EfiBuffer;
     EFI_MEMORY_DESCRIPTOR *EfiMap;
-    BOOLEAN IsRamdisk;
-    MEMORY_TYPE MemoryType;
+    UINTN EfiMapKey;
+    UINTN EfiMapSize, EfiDescriptorSize;
+    UINT32 EfiDescriptorVersion;
     UINT64 EfiStartPage, EfiEndPage;
+    UINTN EfiPageCount;
+    ULONGLONG NtStartPage;
+    ULONG NtPageCount;
+    BOOLEAN IsRamdisk;
     UINT64 EfiRamdiskStartPage, EfiRamdiskEndPage;
+    MEMORY_TYPE MemoryType;
     PMEMORY_DESCRIPTOR NtDescriptor;
 
     (VOID)Flags;
@@ -347,8 +348,8 @@ Return Value:
     }
 
     EfiMapSize += 4 * EfiDescriptorSize;
-    PageCount = (ALIGN_UP(EfiMapSize, PAGE_SIZE) >> PAGE_SHIFT) + 1;
-    EfiPageCount = EFI_PAGE(PageCount);
+    NtPageCount = (ALIGN_UP(EfiMapSize, PAGE_SIZE) >> PAGE_SHIFT) + 1;
+    EfiPageCount = EFI_PAGE(NtPageCount);
     Status = EfiAllocatePages(AllocateAnyPages, EfiLoaderData, EfiPageCount, &EfiBuffer);
     if (!NT_SUCCESS(Status)) {
         DebugPrint(L"MmFwGetMemoryMap(): EfiAllocatePages() failed\r\n");
@@ -572,9 +573,55 @@ Return Value:
     }
 
     //
-    // TODO: Account for possible MDL changes due to freeing EfiBuffer.
+    // The following code is to free the buffer and
+    // also mark the freed memory as free in the MDL.
     //
 
+    Status = EfiFreePages(EfiBuffer, EfiPageCount);
+    if (!NT_SUCCESS(Status)) {
+        Status = STATUS_SUCCESS;
+        goto exit;
+    }
+    EfiBuffer = 0;
+
+    EfiStartPage = EfiBuffer >> EFI_PAGE_SHIFT;
+    EfiEndPage = ALIGN_UP(EfiStartPage + EfiPageCount, EFI_PAGE(1));
+    NtStartPage = NT_PAGE(EfiStartPage);
+    NtPageCount = NT_PAGE(EfiEndPage) - NtStartPage;
+
+    //
+    // Find the current descriptor.
+    //
+    NtDescriptor = MmMdFindDescriptorFromMdl(Mdl, NtStartPage, MDL_OPERATION_FLAGS_PHYSICAL);
+    if (NtDescriptor == NULL) {
+        Status = STATUS_UNSUCCESSFUL;
+        goto exit;
+    }
+
+    //
+    // Create a new free descriptor, with the same
+    // attributes as the current one.
+    //
+    NtDescriptor = MmMdInitDescriptor(NtStartPage, 0, NtPageCount, NtDescriptor->Attributes, MEMORY_TYPE_FREE);
+    if (NtDescriptor == NULL) {
+        Status = STATUS_INSUFFICIENT_RESOURCES;
+        goto exit;
+    }
+
+    //
+    // Remove the current descriptor.
+    //
+    Status = MmMdRemoveRegionFromMdlEx(Mdl, NtStartPage, NtPageCount, MDL_OPERATION_FLAGS_PHYSICAL, 0);
+    if (!NT_SUCCESS(Status)) {
+        MmMdFreeDescriptor(NtDescriptor);
+        goto exit;
+    }
+
+    //
+    // Add the new descriptor to the MDL.
+    //
+    Status = MmMdAddDescriptorToList(Mdl, NtDescriptor, 0x01);
+
 exit:
     if (EfiBuffer) {
         EfiFreePages(EfiBuffer, EfiPageCount);
diff --git a/BOOT/ENVIRON/LIB/MM/mmmd.c b/BOOT/ENVIRON/LIB/MM/mmmd.c
index ec8f037..ffdf89f 100644
--- a/BOOT/ENVIRON/LIB/MM/mmmd.c
+++ b/BOOT/ENVIRON/LIB/MM/mmmd.c
@@ -386,6 +386,45 @@ Return Value:
     }
 }
 
+PMEMORY_DESCRIPTOR
+MmMdFindDescriptorFromMdl (
+    IN PMEMORY_DESCRIPTOR_LIST Mdl,
+    IN ULONGLONG Page,
+    IN ULONG Flags
+    )
+
+/*++
+
+Routine Description:
+
+    Searches an MDL for the descriptor containing a page.
+
+Arguments:
+
+    Mdl - The MDL to search.
+
+    Page - The page to search for.
+
+    Flags - MDL_OPERATION_FLAGS_*
+        MDL_OPERATION_FLAGS_PHYSICAL if Page is physical.
+        MDL_OPERATION_FLAGS_VIRTUAL if Page is virtual.
+
+Return Value:
+
+    Pointer to the descriptor if successful.
+    NULL if an error occurs.
+
+--*/
+
+
+{
+    //
+    // TODO: Implement this routine.
+    //
+
+    return NULL;
+}
+
 NTSTATUS
 MmMdRemoveRegionFromMdlEx (
     IN PMEMORY_DESCRIPTOR_LIST Mdl,