diff --git a/reactos/ntoskrnl/mm/ARM3/i386/init.c b/reactos/ntoskrnl/mm/ARM3/i386/init.c
index 0e6908fcbcd..c0226ebc8ac 100644
--- a/reactos/ntoskrnl/mm/ARM3/i386/init.c
+++ b/reactos/ntoskrnl/mm/ARM3/i386/init.c
@@ -339,7 +339,7 @@ MiInitMachineDependent(IN PLOADER_PARAMETER_BLOCK LoaderBlock)
     MmNonPagedSystemStart = (PVOID)((ULONG_PTR)MmNonPagedPoolStart -
                                     (MmNumberOfSystemPtes + 1) * PAGE_SIZE);
     MmNonPagedSystemStart = (PVOID)((ULONG_PTR)MmNonPagedSystemStart &
-                                    ~((4 * 1024 * 1024) - 1));
+                                    ~(PDE_MAPPED_VA - 1));
     
     //
     // Don't let it go below the minimum
@@ -387,7 +387,7 @@ MiInitMachineDependent(IN PLOADER_PARAMETER_BLOCK LoaderBlock)
     //
     MmPfnDatabase[0] = (PVOID)0xB0000000;
     MmPfnDatabase[1] = &MmPfnDatabase[0][MmHighestPhysicalPage];
-    ASSERT(((ULONG_PTR)MmPfnDatabase[0] & ((4 * 1024 * 1024) - 1)) == 0);
+    ASSERT(((ULONG_PTR)MmPfnDatabase[0] & (PDE_MAPPED_VA - 1)) == 0);
             
     //
     // Non paged pool comes after the PFN database
diff --git a/reactos/ntoskrnl/mm/ARM3/mminit.c b/reactos/ntoskrnl/mm/ARM3/mminit.c
index 5ed08499d98..eba66b18311 100644
--- a/reactos/ntoskrnl/mm/ARM3/mminit.c
+++ b/reactos/ntoskrnl/mm/ARM3/mminit.c
@@ -1725,8 +1725,8 @@ MmArmInitSystem(IN ULONG Phase,
         //
         MmBootImageSize = KeLoaderBlock->Extension->LoaderPagesSpanned;
         MmBootImageSize *= PAGE_SIZE;
-        MmBootImageSize = (MmBootImageSize + (4 * 1024 * 1024) - 1) & ~((4 * 1024 * 1024) - 1);
-        ASSERT((MmBootImageSize % (4 * 1024 * 1024)) == 0);
+        MmBootImageSize = (MmBootImageSize + PDE_MAPPED_VA - 1) & ~(PDE_MAPPED_VA - 1);
+        ASSERT((MmBootImageSize % PDE_MAPPED_VA) == 0);
         
         //
         // Set the size of session view, pool, and image