diff --git a/reactos/ntoskrnl/mm/ARM3/iosup.c b/reactos/ntoskrnl/mm/ARM3/iosup.c
index 08a8ba261d0..2549e922f57 100644
--- a/reactos/ntoskrnl/mm/ARM3/iosup.c
+++ b/reactos/ntoskrnl/mm/ARM3/iosup.c
@@ -144,9 +144,10 @@ MmMapIoSpace(IN PHYSICAL_ADDRESS PhysicalAddress,
         case MiWriteCombined:
 
             //
-            // We don't support write combining yet
+            // Disable the cache and allow combined writing
             //
-            ASSERT(FALSE);
+            MI_PAGE_DISABLE_CACHE(&TempPte);
+            MI_PAGE_WRITE_COMBINED(&TempPte);
             break;
 
         default: