[GUIDE] Make a Reprogrammable Genesis Cart

[shion arita]

I'm having some trouble with my reproduction and want to see if anyone can help troubleshooting.

I'm trying to make Warsong/Langrisser (512k/4Megabit rom w/ SRAM save) using an NBA Live 95 cartridge (2048k/16Megabit rom w/ SRAM save). I used a 27c160 EPROM, and programmed all 4 banks with the Warsong rom file (probably unneccessary but whatever). I soldered it in and I only get a black screen; no license text or anything. I did byteswap the rom file.

Does anyone have an idea of what could be the issue?

Edit: I found the problem(s). First, in my breadboard adapter from the 27c160 to the TL866 two wires were switched. For the record, if Query or Address pins are switched, the chip will appear to program and verify correctly, because all the data will be on the chip, albeit in an incorrect order. But the incorrect wiring will correctly read the incorrect order because it was what was used to program it.

The second problem was that my test cart was using these kind of female headers, which for some reason was not making good contact with the chip legs on the eprom. I resolved this by using a breadboard and jumper wires (which have longer legs). This shouldn't be a problem when I solder it down for real.

However, one issue remains; apparently, NBA Live 96 (which is what the test cart is; 95 is what I soldered the first attempt directly to) does not have the correct amount of SRAM, and i get an error saying as such when I try to save. 95 probably has the same problem. I've looked for a comprehensive list of which games have how much SRAM, like I've been able to find about NES and SNES games that I've made repros of in the past, but I haven't been able to find this info for genesis. Does anyone know where I could find this information?