diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/BxROM.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/BxROM.cs
index b333587a0d..63722da27e 100644
--- a/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/BxROM.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/BxROM.cs
@@ -32,7 +32,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 
 				case "IREM-BNROM": //Mashou (J).nes
 				case "NES-BNROM": //Deadly Towers (U)
-					AssertPrg(128); AssertChr(0); AssertWram(0); AssertVram(8);
+					AssertPrg(128,256); AssertChr(0); AssertWram(0,8); AssertVram(8);
 					break;
 
 				default:
@@ -80,4 +80,4 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 		}
 
 	}
-}
\ No newline at end of file
+}