diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/MMC3_family/Mapper134.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/MMC3_family/Mapper134.cs
index e3943d19cd..e898949ce3 100644
--- a/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/MMC3_family/Mapper134.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/MMC3_family/Mapper134.cs
@@ -38,12 +38,12 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 
 		protected override int Get_PRGBank_8K(int addr)
 		{
-			return base.Get_PRGBank_8K(addr) | ((reg & 0x2) << 4);
+			return (base.Get_PRGBank_8K(addr) &0x1F) | ((reg & 0x2) << 4);
 		}
 
 		protected override int Get_CHRBank_1K(int addr)
 		{
-			return base.Get_CHRBank_1K(addr) | ((reg & 0x20) << 3);
+			return base.Get_CHRBank_1K(addr) | (reg <<3 & 0x100);
 		}
 	}
 }