NES - Start HVC-CNROM-256K-01 board (for mapper 185). Finishing will require finding a rom with the right sha1.

BizHawk.Emulation/BizHawk.Emulation.csproj

@@ -95,6 +95,7 @@
     <Compile Include="Consoles\Nintendo\NES\Boards\GxROM.cs">
       <SubType>Code</SubType>
     </Compile>
+    <Compile Include="Consoles\Nintendo\NES\Boards\HVC_CNROM_256K_01.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\HVC_UN1ROM.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\HVC_UNROM_74HC08.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\IC_74x377.cs">

BizHawk.Emulation/Consoles/Nintendo/NES/Boards/HVC_CNROM_256K_01.cs

@@ -0,0 +1,48 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace BizHawk.Emulation.Consoles.Nintendo
+{
+	class HVC_CNROM_256K_01 : NES.NESBoardBase 
+	{
+		//Mapper 185
+		//Spy Vs. Spy (J)
+		//Mighty Bomb Jack (J)
+
+		int chr;
+
+		public override bool Configure(NES.EDetectionOrigin origin)
+		{
+			//configure
+			switch (Cart.board_type)
+			{
+				case "HVC-CNROM-256K-01": 
+					break;
+				default:
+					return false;
+			}
+			SetMirrorType(Cart.pad_h, Cart.pad_v);
+			return true;
+		}
+
+		public override void SyncState(Serializer ser)
+		{
+			base.SyncState(ser);
+			ser.Sync("chr", ref chr);
+		}
+
+		public override void WritePRG(int addr, byte value)
+		{
+			chr = value;
+		}
+
+		public override byte ReadPPU(int addr)
+		{
+			if (addr < 0x2000)
+				return VROM[addr + (chr * 0x2000)];
+			return base.ReadPPU(addr);
+		}
+	}
+}

BizHawk.MultiClient/output/gamedb.txt

@@ -76,6 +76,7 @@ sha1:8C7D33753649A2BAF2EAAF8D5FFC2AE8E9316A13		Akira (J)	NES		board=TAITO-TC0190
 sha1:0AE47BD83202A5A2235B0BC16278F56D66038AB5		Deathbots (U)	NES		board=AVE-NINA-06;PRG=64;CHR=64;PAD_H=1;PAD_V=0
 
 ;these roms are in goodNES but theyre junk
+sha1:8885F4F00C0B73C156179BCEABA5381487DBEAAD	H	Spy vs Spy (J)	NES		board=HVC-CNROM-256K-01;PRG=32;CHR=8;WRAM=8
 sha1:8C676CC9BEF5B93C5A7630D12B8A5B2FEBCE3438	H	Rad Racket - Deluxe Tennis II	NES		board=NINA-06;PRG=32;CHR=32
 sha1:89C455E1793A1603BB977AD7215AB308B3586958	V	Moero!! Pro Yakyuu (Red)	NES		board=JALECO-JF-13;PRG=128;CHR=64;WRAM=8
 sha1:A906B9E67F0FFCFABB36C9B7140BC2CBA9E1F5A3		Space Shadow (J)	NES		board=BANDAI-74*161/161/32;PRG=64;CHR=128;WRAM=8