diff --git a/reactos/ntoskrnl/include/internal/mm.h b/reactos/ntoskrnl/include/internal/mm.h
index cc74b2fd7ed..e51db265fa1 100644
--- a/reactos/ntoskrnl/include/internal/mm.h
+++ b/reactos/ntoskrnl/include/internal/mm.h
@@ -289,30 +289,68 @@ typedef struct
     ULONG PagingRequestsInLastFifteenMinutes;
 } MM_STATS;
 
-typedef struct _PHYSICAL_PAGE
+typedef struct _MMPFNENTRY
 {
+    USHORT Modified:1;
+    USHORT ReadInProgress:1;                 // StartOfAllocation
+    USHORT WriteInProgress:1;                // EndOfAllocation
+    USHORT PrototypePte:1;                   // Zero
+    USHORT PageColor:4;                      // LockCount
+    USHORT PageLocation:3;                   // Consumer
+    USHORT RemovalRequested:1;
+    USHORT CacheAttribute:2;                 // Type
+    USHORT Rom:1;
+    USHORT ParityError:1;
+} MMPFNENTRY;
+
+typedef struct _MMPFN
+{
+    union
+    {
+        PFN_NUMBER Flink;                    // ListEntry.Flink
+        ULONG WsIndex;
+        PKEVENT Event;
+        NTSTATUS ReadStatus;
+        SINGLE_LIST_ENTRY NextStackPfn;
+    } u1;
+    PMMPTE PteAddress;                       // ListEntry.Blink
+    union
+    {
+        PFN_NUMBER Blink;
+        ULONG_PTR ShareCount;                // MapCount
+    } u2;
     union
     {
         struct
         {
-            ULONG Type: 2;
-            ULONG Consumer: 3;
-            ULONG Zero: 1;
-            ULONG StartOfAllocation: 1;
-            ULONG EndOfAllocation: 1;
-        }
-        Flags;
-        ULONG AllFlags;
+            USHORT ReferenceCount;           // ReferenceCount
+            MMPFNENTRY e1;
+        };
+        struct
+        {
+            USHORT ReferenceCount;
+            USHORT ShortFlags;
+        } e2;
+    } u3;
+    union
+    {
+        MMPTE OriginalPte;
+        LONG AweReferenceCount;              // RmapListHead
     };
-
-    LIST_ENTRY ListEntry;
-    ULONG ReferenceCount;
-    SWAPENTRY SavedSwapEntry;
-    ULONG LockCount;
-    ULONG MapCount;
-    struct _MM_RMAP_ENTRY* RmapListHead;
-}
-PHYSICAL_PAGE, *PPHYSICAL_PAGE;
+    union
+    {
+        ULONG_PTR EntireFrame;               // SavedSwapEntry
+        struct
+        {
+            ULONG_PTR PteFrame:25;
+            ULONG_PTR InPageError:1;
+            ULONG_PTR VerifierAllocation:1;
+            ULONG_PTR AweAllocation:1;
+            ULONG_PTR Priority:3;
+            ULONG_PTR MustBeCached:1;
+        };
+    } u4;
+} MMPFN, *PMMPFN;
 
 extern MM_STATS MmStats;
 
@@ -991,14 +1029,14 @@ MmPageOutPhysicalAddress(PFN_TYPE Page);
 
 /* freelist.c **********************************************************/
 
-#define ASSERT_PFN(x) ASSERT((x)->Flags.Type != 0)
+#define ASSERT_PFN(x) ASSERT((x)->u3.e1.CacheAttribute != 0)
 
 FORCEINLINE
-PPHYSICAL_PAGE
+PMMPFN
 MiGetPfnEntry(IN PFN_TYPE Pfn)
 {
-    PPHYSICAL_PAGE Page;
-    extern PPHYSICAL_PAGE MmPageArray;
+    PMMPFN Page;
+    extern PMMPFN MmPageArray;
     extern ULONG MmPageArraySize;
 
     /* Mark MmPageArraySize as unreferenced, otherwise it will appear as an unused variable on a Release build */
@@ -1278,16 +1316,6 @@ BOOLEAN
 NTAPI
 MmIsPageInUse(PFN_TYPE Page);
 
-VOID
-NTAPI
-MmSetFlagsPage(
-    PFN_TYPE Page,
-    ULONG Flags);
-
-ULONG
-NTAPI
-MmGetFlagsPage(PFN_TYPE Page);
-
 VOID
 NTAPI
 MmSetSavedSwapEntryPage(
diff --git a/reactos/ntoskrnl/mm/balance.c b/reactos/ntoskrnl/mm/balance.c
index 9d05b34a2b2..c7de8152745 100644
--- a/reactos/ntoskrnl/mm/balance.c
+++ b/reactos/ntoskrnl/mm/balance.c
@@ -277,7 +277,7 @@ MmRequestPageMemoryConsumer(ULONG Consumer, BOOLEAN CanWait,
          KeBugCheck(NO_PAGES_AVAILABLE);
       }
       /* Update the Consumer */
-      MiGetPfnEntry(Page)->Flags.Consumer = Consumer;
+      MiGetPfnEntry(Page)->u3.e1.PageLocation = Consumer;
       if(Consumer == MC_USER) MmInsertLRULastUserPage(Page);
       *AllocatedPage = Page;
       (void)InterlockedDecrementUL(&MiPagesRequired);
diff --git a/reactos/ntoskrnl/mm/freelist.c b/reactos/ntoskrnl/mm/freelist.c
index bbb517cdaf4..920dc43f08d 100644
--- a/reactos/ntoskrnl/mm/freelist.c
+++ b/reactos/ntoskrnl/mm/freelist.c
@@ -27,6 +27,27 @@
 
 /* GLOBALS ****************************************************************/
 
+//
+//
+// ReactOS to NT Physical Page Descriptor Entry Legacy Mapping Definitions
+//
+//        REACTOS                 NT
+//
+#define Consumer             PageLocation
+#define Type                 CacheAttribute
+#define Zero                 PrototypePte
+#define LockCount            u3.e1.PageColor
+#define MapCount             u2.ShareCount
+#define RmapListHead         AweReferenceCount
+#define SavedSwapEntry       u4.EntireFrame
+#define Flags                u3.e1
+#define ReferenceCount       u3.ReferenceCount
+#define RemoveEntryList(x)   RemoveEntryList((PLIST_ENTRY)x)
+#define InsertTailList(x, y) InsertTailList(x, (PLIST_ENTRY)y)
+#define ListEntry            u1
+#define PHYSICAL_PAGE        MMPFN
+#define PPHYSICAL_PAGE       PMMPFN
+
 PPHYSICAL_PAGE MmPageArray;
 ULONG MmPageArraySize;
 
@@ -94,7 +115,7 @@ MmGetLRUNextUserPage(PFN_TYPE PreviousPfn)
    Page = MiGetPfnEntry(PreviousPfn);
    ASSERT(Page->Flags.Type == MM_PHYSICAL_PAGE_USED);
    ASSERT(Page->Flags.Consumer == MC_USER);
-   NextListEntry = Page->ListEntry.Flink;
+   NextListEntry = (PLIST_ENTRY)Page->ListEntry.Flink;
    if (NextListEntry == &UserPageListHead)
    {
 	  KeReleaseQueuedSpinLock(LockQueuePfnLock, oldIrql);
@@ -295,10 +316,12 @@ MmInitializePageList(VOID)
          NextEntry != &KeLoaderBlock->MemoryDescriptorListHead;
          NextEntry = NextEntry->Flink)
     {
+#undef ListEntry
         /* Get the descriptor */
         Md = CONTAINING_RECORD(NextEntry,
                                MEMORY_ALLOCATION_DESCRIPTOR,
                                ListEntry);
+#define ListEntry            u1        
 
         /* Skip bad memory */
         if ((Md->MemoryType == LoaderFirmwarePermanent) ||
@@ -366,17 +389,6 @@ MmInitializePageList(VOID)
     MmInitializeBalancer(MmStats.NrFreePages, MmStats.NrSystemPages);
 }
 
-VOID
-NTAPI
-MmSetFlagsPage(PFN_TYPE Pfn, ULONG Flags)
-{
-   KIRQL oldIrql;
-
-   oldIrql = KeAcquireQueuedSpinLock(LockQueuePfnLock);
-   MiGetPfnEntry(Pfn)->AllFlags = Flags;
-   KeReleaseQueuedSpinLock(LockQueuePfnLock, oldIrql);
-}
-
 VOID
 NTAPI
 MmSetRmapListHeadPage(PFN_TYPE Pfn, struct _MM_RMAP_ENTRY* ListHead)
@@ -384,7 +396,7 @@ MmSetRmapListHeadPage(PFN_TYPE Pfn, struct _MM_RMAP_ENTRY* ListHead)
    KIRQL oldIrql;
     
    oldIrql = KeAcquireQueuedSpinLock(LockQueuePfnLock);
-   MiGetPfnEntry(Pfn)->RmapListHead = ListHead;
+   MiGetPfnEntry(Pfn)->RmapListHead = (LONG)ListHead;
    KeReleaseQueuedSpinLock(LockQueuePfnLock, oldIrql);
 }
 
@@ -396,7 +408,7 @@ MmGetRmapListHeadPage(PFN_TYPE Pfn)
    struct _MM_RMAP_ENTRY* ListHead;
     
    oldIrql = KeAcquireQueuedSpinLock(LockQueuePfnLock);
-   ListHead = MiGetPfnEntry(Pfn)->RmapListHead;
+   ListHead = (struct _MM_RMAP_ENTRY*)MiGetPfnEntry(Pfn)->RmapListHead;
    KeReleaseQueuedSpinLock(LockQueuePfnLock, oldIrql);
     
    return(ListHead);
@@ -451,29 +463,14 @@ MmMarkPageUnmapped(PFN_TYPE Pfn)
    }
 }
 
-ULONG
-NTAPI
-MmGetFlagsPage(PFN_TYPE Pfn)
-{
-   KIRQL oldIrql;
-   ULONG Flags;
-
-   oldIrql = KeAcquireQueuedSpinLock(LockQueuePfnLock);
-   Flags = MiGetPfnEntry(Pfn)->AllFlags;
-   KeReleaseQueuedSpinLock(LockQueuePfnLock, oldIrql);
-
-   return(Flags);
-}
-
-
 VOID
 NTAPI
-MmSetSavedSwapEntryPage(PFN_TYPE Pfn,  SWAPENTRY SavedSwapEntry)
+MmSetSavedSwapEntryPage(PFN_TYPE Pfn,  SWAPENTRY SwapEntry)
 {
    KIRQL oldIrql;
 
    oldIrql = KeAcquireQueuedSpinLock(LockQueuePfnLock);
-   MiGetPfnEntry(Pfn)->SavedSwapEntry = SavedSwapEntry;
+   MiGetPfnEntry(Pfn)->SavedSwapEntry = SwapEntry;
    KeReleaseQueuedSpinLock(LockQueuePfnLock, oldIrql);
 }
 
@@ -481,14 +478,14 @@ SWAPENTRY
 NTAPI
 MmGetSavedSwapEntryPage(PFN_TYPE Pfn)
 {
-   SWAPENTRY SavedSwapEntry;
+   SWAPENTRY SwapEntry;
    KIRQL oldIrql;
 
    oldIrql = KeAcquireQueuedSpinLock(LockQueuePfnLock);
-   SavedSwapEntry = MiGetPfnEntry(Pfn)->SavedSwapEntry;
+   SwapEntry = MiGetPfnEntry(Pfn)->SavedSwapEntry;
    KeReleaseQueuedSpinLock(LockQueuePfnLock, oldIrql);
 
-   return(SavedSwapEntry);
+   return(SwapEntry);
 }
 
 VOID
@@ -591,7 +588,7 @@ MmDereferencePage(PFN_TYPE Pfn)
       MmStats.NrFreePages++;
       MmStats.NrSystemPages--;
       if (Page->Flags.Consumer == MC_USER) RemoveEntryList(&Page->ListEntry);
-      if (Page->RmapListHead != NULL)
+      if (Page->RmapListHead != (LONG)NULL)
       {
          DPRINT1("Freeing page with rmap entries.\n");
          KeBugCheck(MEMORY_MANAGEMENT);
@@ -636,7 +633,7 @@ NTAPI
 MmGetLockCountPage(PFN_TYPE Pfn)
 {
    KIRQL oldIrql;
-   ULONG LockCount;
+   ULONG CurrentLockCount;
    PPHYSICAL_PAGE Page;
 
    DPRINT("MmGetLockCountPage(PhysicalAddress %x)\n", Pfn << PAGE_SHIFT);
@@ -650,10 +647,10 @@ MmGetLockCountPage(PFN_TYPE Pfn)
       KeBugCheck(MEMORY_MANAGEMENT);
    }
 
-   LockCount = Page->LockCount;
+   CurrentLockCount = Page->LockCount;
    KeReleaseQueuedSpinLock(LockQueuePfnLock, oldIrql);
 
-   return(LockCount);
+   return(CurrentLockCount);
 }
 
 VOID
@@ -711,7 +708,7 @@ MmUnlockPage(PFN_TYPE Pfn)
 
 PFN_TYPE
 NTAPI
-MmAllocPage(ULONG Consumer, SWAPENTRY SavedSwapEntry)
+MmAllocPage(ULONG Consumer, SWAPENTRY SwapEntry)
 {
    PFN_TYPE PfnOffset;
    PLIST_ENTRY ListEntry;
@@ -774,7 +771,7 @@ MmAllocPage(ULONG Consumer, SWAPENTRY SavedSwapEntry)
    PageDescriptor->ReferenceCount = 1;
    PageDescriptor->LockCount = 0;
    PageDescriptor->MapCount = 0;
-   PageDescriptor->SavedSwapEntry = SavedSwapEntry;
+   PageDescriptor->SavedSwapEntry = SwapEntry;
 
    MmStats.NrSystemPages++;
    MmStats.NrFreePages--;
diff --git a/reactos/ntoskrnl/mm/mminit.c b/reactos/ntoskrnl/mm/mminit.c
index 684f912fdd1..4236cda457c 100644
--- a/reactos/ntoskrnl/mm/mminit.c
+++ b/reactos/ntoskrnl/mm/mminit.c
@@ -403,7 +403,7 @@ MmInit1(VOID)
 
     /* We'll put the PFN array right after the loaded modules */
     MmPfnDatabase = (PVOID)MiKSeg0End;
-    MmPfnDatabaseEnd = (ULONG_PTR)MmPfnDatabase + (MmHighestPhysicalPage * sizeof(PHYSICAL_PAGE));
+    MmPfnDatabaseEnd = (ULONG_PTR)MmPfnDatabase + (MmHighestPhysicalPage * sizeof(MMPFN));
     MmPfnDatabaseEnd = PAGE_ROUND_UP(MmPfnDatabaseEnd);
     
     /*