diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/MMC3_family/TLSROM.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/MMC3_family/TLSROM.cs
index 29a489e96d..7761ab4680 100644
--- a/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/MMC3_family/TLSROM.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/MMC3_family/TLSROM.cs
@@ -21,8 +21,14 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 					AssertBattery(true);
 					break;
 				case "TENGEN-800037": //Alien Syndrome (U)
+					// this board is actually a RAMBO-1 (mapper064) with TLS-style rewiring
+					// but it seems to work fine here, so lets not worry about it
 					AssertPrg(128); AssertChr(128); AssertVram(0); AssertWram(0);
 					break;
+				case "MAPPER158":
+					// as above
+					AssertVram(0); Cart.wram_size = 0;
+					break;
 				case "HVC-TLSROM":
 					AssertPrg(256); AssertChr(128); AssertVram(0); AssertWram(0);
 					break;