Unable to Dump Game Genie ROM (Genesis/Mega Drive)

[PW5190]

Hey, I have a problem with my SEGA Genesis Game Genie cheating device.

I put it into the SEGA Genesis/MD slot, set the volt switch to 5V, and left the EEP, CLK0, and CLK1 switches off.

I then turned on my OSCR, and navigated to the Mega Drive section, then selected Game Cartridge. Here's the stats:

Cart Info:

Name: GameGenie
bramCheck: 0100
Size: 0 MBit
ChkS: 0000
Sram: None

I then pressed Read Rom, and I got an error:

Saving to MD/ROM/Game
Genie/47/...
[*******************]
Internal checksum...E
rror
37C7

CRC: Glitched

I tried it both with and without another Genesis game on top, and it won't dump the ROM.

[sanni]

Try updating to 12.4 to see if that changes anything.

[PW5190]

I'm having a little trouble manually updating the firmware for my OSCR. Is there a way to automate the update process?

[sanni]

Easiest way would be to download V12.3_Portable.zip extract it, go into the V12.3_Portable\Arduino IDE Portable\portable\sketchbook\Cart_Reader\ directory and delete all files there. Then copy the same files from 12.4 into that directory and follow the readme.txt

[PW5190]

OK, I updated, and was able to dump the Game Genie ROM. The OSCR still thinks there's an error, but it dumped anyway. I threw the ROM in Kega Fusion, and discovered the checksum for the ROM was incorrect, but it did boot into the code entry page.

[sanni]

In the no-intro set there are two Game Genie dumps, both are 32KB in size.

Game Genie (USA, Europe) (Rev A) (Program).md
CRC32: 14DBCE4A

Game Genie (USA, Europe) (Program).md
CRC32: 5F293E4C

Your dump probably is 128KB since that is the smallest size I set. So what you can try is to to change both occurrences of 0x20000 to 0x8000 in MD.ino line 1097

Change:

  // Some games are missing the ROM size in the header, in this case calculate ROM size by looking for mirror of the first line of the ROM
  // This does not work for cartridges that have SRAM mapped directly after the maskrom like Striker (Europe)
  if ((cartSize < 0x8000) || (cartSize > 0xEAF400)) {
    for (cartSize = 0x20000 / 2; cartSize < 0x400000 / 2; cartSize += 0x20000 / 2) {
      if ((readWord_MD(0x0) == readWord_MD(cartSize)) && (readWord_MD(0x1) == readWord_MD(0x1 + cartSize)) && (readWord_MD(0x2) == readWord_MD(0x2 + cartSize)) && (readWord_MD(0x3) == readWord_MD(0x3 + cartSize)) && (readWord_MD(0x4) == readWord_MD(0x4 + cartSize)) && (readWord_MD(0x5) == readWord_MD(0x5 + cartSize)) && (readWord_MD(0x6) == readWord_MD(0x6 + cartSize)) && (readWord_MD(0x7) == readWord_MD(0x7 + cartSize)) && (readWord_MD(0x8) == readWord_MD(0x8 + cartSize))) {
        break;
      }
    }
    cartSize = cartSize * 2;
  }

to:

  // Some games are missing the ROM size in the header, in this case calculate ROM size by looking for mirror of the first line of the ROM
  // This does not work for cartridges that have SRAM mapped directly after the maskrom like Striker (Europe)
  if ((cartSize < 0x8000) || (cartSize > 0xEAF400)) {
    for (cartSize = 0x8000 / 2; cartSize < 0x400000 / 2; cartSize += 0x8000 / 2) {
      if ((readWord_MD(0x0) == readWord_MD(cartSize)) && (readWord_MD(0x1) == readWord_MD(0x1 + cartSize)) && (readWord_MD(0x2) == readWord_MD(0x2 + cartSize)) && (readWord_MD(0x3) == readWord_MD(0x3 + cartSize)) && (readWord_MD(0x4) == readWord_MD(0x4 + cartSize)) && (readWord_MD(0x5) == readWord_MD(0x5 + cartSize)) && (readWord_MD(0x6) == readWord_MD(0x6 + cartSize)) && (readWord_MD(0x7) == readWord_MD(0x7 + cartSize)) && (readWord_MD(0x8) == readWord_MD(0x8 + cartSize))) {
        break;
      }
    }
    cartSize = cartSize * 2;
  }

And then see if it dumps a 32KB ROM.