Breath of Fire 2 SPC hacking

Exactly, since this NPC triggers an event that swaps the pointers in the ROM itself. Pinpointing it would be a real PITA to say the least. Unfortunately, no one has accepted the challenge to do so.

Where did you get that info ? No matter what you change in a game by playing it, it will most likely never overwrite or swap data in the ROM. I'm not going to read the whole thread, but you song swapping is probably a flag set in the RAM, that's it.

Do you think every item you get or the stats of your player are overwritten in the ROM in real time ? That's the job of the RAM. Now there is SRAM, which is saved when you save your game. Your song swapping is probably a bit set in the SRAM. The only thing is that you need to know which bit is concerned and for that, disassemble some code. There is no magic trick. You could try it.

For the same reason mentioned above this won't work, unless you do it for the SRAM, if you know where it is located:

I've never tried anything like this, but if I wanted it to happen I'd probably try this - setup Geiger's SPC debugger, then trigger a random encounter, with the old music. Then, go trip the variable to change the battle music. Then, attempt to get into the same random encounter with EVERYTHING else being the same, such as inventory, party members, hp, etc. then parse the two logs and try to "find the differences". If you're lucky, only a few bytes will be different, allowing you to laser in your focus on just a few possibilities.