Has anyone ever successfully replaced one of the backgrounds in Final Fantasy IV Advance? I've been looking into it and it appears that the way the tileset and tilemap are handled aren't your standard GBA tilesets and tilemaps that you could whip up in Nameless Tilemap Editor (for example), as each tileset has non-graphic data bytes at the beginning, as for the tilemap, no current tilemap editor can get it to display the proper size.
Here is what I've found, offsets are for the European FFIV Advance:
0x0FA1BC - Battle BG Tileset table
0x0FA218 - Battle BG Palette table
0x0FA274 - Battle BG Tilemap table
I'm trying to replace the backgrounds with the darker-colored ones from the PSP version since I someday plan on doing a color restoration hack and other overhauls of FFIV Advance, restoring it to the WonderSwan colors. (Yes, I shrunk down, cropped, and indexed the background before inserting into the GBA ROM).
Here is my most current attempt at replacing one of the backgrounds:
For some reason even though in NTME the tileset+tilemap appears normal, and I've been careful to give the correct palette assignments, it still appears like crap in-game. I've tried various tilemap dimensions (32x32 blocks, 34x17 blocks, 36x15 blocks, etc.) and none of them make it work properly in-game.
Has anyone else ever tried to do tileset+tilemap hacking on the GBA and could possibly know what kind of weird stuff FFIVA's tilemaps are doing? I've done it with the Pokemon games and never had any problems.