An odd bug in Sonic 1: The Special Stages

Well, here's a little copypasta from Retro I made.


Well, there is a bug, which is quite odd. After you've played through the seventh Special Stage, you'll be warped randomly to another special stage with wrong start location and music.


MarkeyJester and I tried to fix this, but with no luck. And my question is, if someone can help me or at least giving a hint.


If you need to know some code, I could post it--or rather PM it.

 

From just that information, it sounds like certain code is misinterpretting the "next" special stage you need to go to, possibly to do with the actual value in RAM being used for the next special stage. Code would be helpful, but I'd also suggest downloading an emulator like Gens KMod with the ability to watch RAM as it changes, and watch values for expected (and in this case, unexpected) data to try and find the problem.

 

I'm going to take a wild guess here, and ask does it always go to the same special stage, and the same position, with the same music? If so, then fixing it shouldn't be too hard. You see, when I was experimenting with changing the level number, if the value is for an act that is nonexistant, then it would normally wrap around. #4 would be GHZ Act 1, just fucked up, and #5 would be Act 2 all fucked up etc.


So most likely if you add more special stages, then it shouldn't fuck up.

 

Well, if you're interested for further information, grab the torrent from below--since my connection crashed sometimes, which leads that I can't upload big files on sites or even on my own FTP.


Torrent File