diff --git a/memmap.cpp b/memmap.cpp
index 27dc12f4..7061c62f 100644
--- a/memmap.cpp
+++ b/memmap.cpp
@@ -2950,6 +2950,9 @@ void CMemory::map_LoROMSRAM (void)
 {
         uint32 hi;
 
+        if (SRAMSize == 0)
+            return;
+
         if (ROMSize > 11 || SRAMSize > 5)
             hi = 0x7fff;
         else