@lion Hey! Sorry to bother you, but I have a weird ROM I've been trying to get working. A SNES one from a multicart that isn't available elsewhere. I was able to get *something* by overdumping, and even got it booting with garbled graphics... but I'm dreadful with this stuff, so I was wondering if you might know of some tools I could try, to figure out the compression at play and how to decompress the data.
Or if you happen to know anything about "Woodi SFC Test" this cart and others report as.
@DanaTheElf I don't have experience with SNES specifically but the usual issue with multicarts isn't compression but rather that they use custom memory mappers that standard dumping tools don't support and typically aren't emulated either. if you're trying to extract a specific game the issue is probably either the full data for that game wasn't dumped or it's not in the right place, but couldn't say which without seeing it really
@DanaTheElf You might have already seen this but if it helps any this person seems to have been successful in extracting games from a Woodi SFC cart https://github.com/sanni/cartreader/discussions/822
@lion Yeah, that's what convinced me to overdump it - I got *something* from it, but it should have ~9.5MB of games on it and I got a repeating 4MB or so, which made me think compression.
Unless it *is* the mapper and I was able to get the game I was after because it was the last one I booted, maybe...
I'm a bit out of my depth, haha. Thanks, though!
@DanaTheElf Yeah that sounds like a mapper thing, what's probably happening is it has multiple 4MB rom banks and requires some specific write to some address to read any other banks, otherwise it'll just give you the first one. The only way to dump the whole thing would be to use a dumping device that allows you to customise the reads/writes performed and then reverse engineer the menu code to figure out what they are, its not trivial sadly
@DanaTheElf It does sound like you mightve been lucky enough that the game you want is present in the first bank in which case you might have all the data & the issue could just be that its not in the right place or the emulator is detecting the size wrong or something
But if you're not lucky the data was split across bank boundaries and you don't have all of it
@lion It's specifically the Aeon Genesis translated version of Magical Drop II, so I've got a clean JP version to compare it to.
With small hex changes I can get the dump to boot, but as I make more small hex changes, I find it un-garbles, but reverts to the original JP appearance. So I guess there's some sort of on-the-fly graphical redirection... which may yet mean there's an issue of compression to tackle...
@DanaTheElf hm if it was only ever released on that cart it's also possible it specifically makes use of the multicart's bank switching to swap in translated assets or something 
@DanaTheElf Yeah it's not too likely tbh but I couldn't totally rule it out
Probably your best bet though is to speak to someone with decent SNES technical knowledge, they could probably figure out the issue pretty easily, i'm just generalising from my experience with GB stuff here
@lion Definitely a possibility, though since the cart was produced by Retro-Bit and the translation by Aeon Genesis, that sort of feels like a strange extra step to take...
Still, anything is possible when trying to prevent something unique from being dumped and shared online, heh. My partner is really interested in documenting the precise differences between the Aeon Genesis version and the one that was released on NSO, so it would be very helpful to have a version that can play in emulation.