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I have found what seems a sound bug I caused to my ROM. It happens "randomly", and so far every time it happens is with the trainer victory song: one of the channels seems to start 5 seconds too late. Turning on and off every channel and comparing the sound to a video I managed to get of it seems it happens to the channel #2.
Is there any way to find what is causing it using bgb debugger or something? I can always undo things on a backup ROM until it stops, but as it rarely happens and I am unnable to find something in common it will take a lot of time to be sure it is gone...
Edit: Just searched wich adresses in RAM are used for the sound, and compared two savestates when the bug is active or not. The only difference is that $FF16 value is BF when the song is correct and 3F when it is playing wrong.
Last edited by Montblanc (2016-08-11 02:18:24)
This might not help but I found this a while ago (wording makes it sound like you keep backups of previous versions, unless I'm misunderstanding.)
I guess unless/until somebody else comes along with a better answer, this could be something to try in the meantime.
The example here is a GBA hack but I don't see why this would work differently for GB (unless you use disassembly and every new version of the rom becomes massively different or something.)
Last edited by Ammako (2016-08-11 05:42:45)
Thanks for your reply!
Yes, I've made the backups for that purpose, each time I made changes in a new part of the ROM (or a new type of data) the original was left and I made a new file with the changes, so each copy is only a few bytes different. But since the bug happens randomly It will take a lot of time to find wich ROMs are affected and wich ones doesn't, it is not something I can trigger :(
I managed to induce the bug even on a retail ROM just by importing a battery file, continuing the game normally and defeating a trainer over and over until the bug happens and the victory music is glitched.
How is this possible? A save file contains data able to glitch the sound randomly? I have been using the same .sav file while making some last changes to the ROM.
You can do a loooooot of things with just a save file and a retail rom. :p
That being said, you haven't been able to get this bug to happen when using a save file created by retail rom yeah?