diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/CNROM.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/CNROM.cs
index 9aa698eb5a..1e4c0ce174 100644
--- a/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/CNROM.cs
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/CNROM.cs
@@ -38,6 +38,8 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 				case "AVE-74*161":
 					AssertPrg(32); AssertChr(64);
 					break;
+				case "MAPPER3":
+					break;
 				default:
 					return false;
 
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/ExROM.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/ExROM.cs
index 0ca966e03d..03f5573d61 100644
--- a/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/ExROM.cs
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/ExROM.cs
@@ -91,6 +91,8 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 				case "NES-ELROM": //Castlevania 3 - Dracula's Curse (U)
 					AssertPrg(128,256); AssertChr(128);
 					break;
+				case "MAPPER5":
+					break;
 				default:
 					return false;
 			}
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/iNES.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/iNES.cs
index 9c90fc9faf..552c4c2c53 100644
--- a/BizHawk.Emulation/Consoles/Nintendo/NES/iNES.cs
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/iNES.cs
@@ -87,10 +87,12 @@ static string ClassifyTable = @"
 2	256	0	8	0	NES-UOROM; paperboy 2
 2	128	0	8	8	HVC-UNROM; JJ - Tobidase Daisakusen Part 2 (J)
 3	32	32	8	0	NES-CNROM; adventure island
+3	-1	-1	-1	-1	MAPPER3
 4	128	128	8	0	NES-TSROM; double dragon 2 (should be TL1ROM but maybe this will work)
 4	256	256	8	0	NES-TKROM; Aces - Iron Eagle 3 (J)
 4	512	128	8	0	NES-TKROM; Pool of radiance (J)
 4	-1	-1	-1	-1	TXROM-HOMEBREW; assorted homebrew junks (incl blargg's mmc3 tests)
+5	-1	-1	-1	-1	MAPPER5
 7	128	0	8	0	NES-ANROM; marble madness
 7	256	0	8	8	NES-AOROM; battletoads
 11	-1	-1	-1	-1	Discrete_74x377-FLEX; Bible Adventures (U) ?