SF2 CE - Question about Rom Hacks

[SF2 Pinball]

Hey all,

I'm curious about the nature of the various ROM hacks I've seen for Street Fighter II: Champion Edition. Were these created by modifying the source code directly and recompiling, or were they made by editing the raw data within the ROM dump?

The reason I'm asking is that I'm interested in the feasibility of creating a custom ROM hack with a secret button combo that would allow me to jump to specific parts of the game, like the car crush bonus round, and then return to the attract screen. But I eventually would want this to run on genuine hardware too. Is this something that's possibile given the way these ROM hacks are typically made?

What about something as simple as renaming "Champion Edition" to say "Custom Edition" ? If that was the only change done, are there checksums in place that might fail when putting it back on an EPROM and playing on CPS1 Hardware?

Any insights would be greatly appreciated

 

[Darksoft]

Looking at all the SF2 hacks that I've seen they are always based on an original version and then patches are applied, but the rest of the code remains the same and in the same place. If you would have the source code and recompile, that wouldn't be the case and the code would be slightly shifted. So that clearly means IMO that they were taking the code to a 68000 based computer like Amiga or ATARI and decompiling from there. You would be able to see the code and even trace it somehow, as the gfx wouldnt be compatible with the host.

Nowadays, thanks to MAME you can do that yourself, and see immediately the effect of your changes. Most games have CRC checks in place, but those are relatively easy to bypass, specially if you debug them with MAME. the other changes that you mention will require a significant amount of hours and you to both understand how the machine works (looking at the MAME driver would help a lot) and also be able to apply patches to the existing roms.

If you have the time, go for it. I'm sure you'll learn a lot in the process.

 

[BilonFullHDemon]

Rom hacking is fun and addictive. I've been there, done that, I'm out!