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General Category => Support => Topic started by: BowzasaurusRex on 29/Dec/2018 10:54:59 PM

Title: Can't dump Felix the Cat (unlicensed game for the Sega Genesis)
Post by: BowzasaurusRex on 29/Dec/2018 10:54:59 PM
Hi. I have a copy of Felix the Cat for the Genesis that I'm trying to dump, but I can't get it to dump properly for some reason.

The cartridge itself works fine on a real Genesis, but when I try to dump it with my Retrode 2 and run it on an emulator I just get a blank screen. I get the exact same result every time I try to dump it (I always get the same checksum when I generate one after dumping the game), and I know for a fact that the Retrode is dumping something from the game as I can see some notes from the developer if I open the rom with a hex editor.

I was able to find an MD5 checksum for this game, but it doesn't match my attempts at dumping it unfortunately

I was able to dump another unlicensed game with the same board just fine using my Retrode 2, but while that game has a chip, this one has a glob top.
Here's a photo of the board for two games, the one on the right is the one I can't dump (

Does anyone know how I might be able to get this game dumped, or perhaps patch it? (I've read that some unlicensed games need to be patched before they can be emulated, but I couldn't find anything for this game)
Title: Re: Can't dump Felix the Cat (unlicensed game for the Sega Genesis)
Post by: ssokolow on 31/Dec/2018 02:31:32 AM
The first thing I'd do is try to get more information to narrow things down.

For example, see if you can find solid information on whether the emulator you're trying can play a known-good dump of that specific game.  If not, or if you can't be sure, try to find another emulator which is confirmed to work with known good dumps of it.

I've only ever dumped three ROMs for Genesis with my Retrode (Sonic 2, Sonic & Knuckles, and Sonic 2 & Knuckles), but I know Gameboy Advance ROMs are susceptible to overdump, since they don't specify their size internally. Maybe something about the cart's header is confusing the Retrode into dumping the wrong range of memory addresses.

Check the sizes listed on dat-o-matic to see if what you're dumping is the right size.

If it's too big, try truncating the file and re-hashing it. If it's too small, try using the Retrode option to override auto-detection and force a dump size. (You may need to dump more and then truncate the result, since the retrode's forced dump sizes don't let you specify a size down to individual bytes.)

Check sites like dat-o-matic for evidence of either the hash you have now or any hashes you get from experimenting with size-forcing and truncating. (If nothing else, maybe you'll find dat-o-matic reporting that it's a broken dump that various members managed to independently confirm as broken.)

Also, I can't endorse piracy, but, if you have a way to get a known good dump through other means, you could try comparing the contents of the two files in various ways to see if you can identify contents of one file within the other, but incomplete or misaligned somehow.
Title: Re: Can't dump Felix the Cat (unlicensed game for the Sega Genesis)
Post by: BowzasaurusRex on 31/Dec/2018 02:32:12 PM
Thank you so much! I was able to find the correct rom size, and it dumped correctly after setting forceSize to 8 and forceSystem to mdrv
Title: Re: Can't dump Felix the Cat (unlicensed game for the Sega Genesis)
Post by: ssokolow on 07/Jan/2019 01:07:45 AM
Glad I could help. :)