Firstly, yeah I know there's a subreddit for this romhack, and they all are being pansies about legal concerns. Whatever, it's not like I'm selling this thing.
Anyways.
I'm trying to play a romhack of Kirby's Dream Course on my SNES! The romhack is applied to the Japanese version. I'm trying to do this without damaging any original PCBs. But there's a multilayer copy protection getting in my way! Darn! I think the best way to proceed would be to edit the rom and skip the copyright checks.
I'm not helpless with 6502, but I've never done any spectacular romhacking before. Never touched an sfc file, to boot. But I feel like this is very possible. I just don't know what tools I ought to use.
6502 disassemblers? Nonspecific 6502 assembler? Snes debugging emulator? I think I'll need all these. My targets are:
1) SRAM size check. From what I can tell the game only checks the SRAM on boot, so I should be able to just JMP right past the check. I have no idea what the SNES sets the PC to on boot though. I'd also need to disassemble the hex, because I'm not a wizard. What tools do I need to find the boot routine? What's a recommended disassembler?
2) Checksum. This seems trickier. I'd imagine my cart will fail this test since Kirby Bowl is 2MB and my cart is 4MB. I imagine this is done by getting a checksum from the rom and then doing a simple comparison to X. So, I think I'd need to find the routine that handles the checksum, figure out what my cart evaluates to, and then replace X with that. I figure this would be really simple with a debugger, I could just step through the checksum routine. No idea how to find that, but I do know of an action replay code that sets off the copyright protection, so could I trace this back?
ANY input valued!
Anyways.
I'm trying to play a romhack of Kirby's Dream Course on my SNES! The romhack is applied to the Japanese version. I'm trying to do this without damaging any original PCBs. But there's a multilayer copy protection getting in my way! Darn! I think the best way to proceed would be to edit the rom and skip the copyright checks.
I'm not helpless with 6502, but I've never done any spectacular romhacking before. Never touched an sfc file, to boot. But I feel like this is very possible. I just don't know what tools I ought to use.
6502 disassemblers? Nonspecific 6502 assembler? Snes debugging emulator? I think I'll need all these. My targets are:
1) SRAM size check. From what I can tell the game only checks the SRAM on boot, so I should be able to just JMP right past the check. I have no idea what the SNES sets the PC to on boot though. I'd also need to disassemble the hex, because I'm not a wizard. What tools do I need to find the boot routine? What's a recommended disassembler?
2) Checksum. This seems trickier. I'd imagine my cart will fail this test since Kirby Bowl is 2MB and my cart is 4MB. I imagine this is done by getting a checksum from the rom and then doing a simple comparison to X. So, I think I'd need to find the routine that handles the checksum, figure out what my cart evaluates to, and then replace X with that. I figure this would be really simple with a debugger, I could just step through the checksum routine. No idea how to find that, but I do know of an action replay code that sets off the copyright protection, so could I trace this back?
ANY input valued!