The "PPU race condition" occurs when a Y-increment triggers after a $2006 (second) write, which should win. Games that are affected by this thing are Mega Man 5, The Simpsons - Bart vs Space Mutants, Kick Master, among others.
A way of fixing it is to put a flag that indicates a $2006 2nd write. If this flag is raised on Y-increment, the increment won't occur after PPU cycle 254 (or 255 depending of how you're counting cycles).
I wonder if this is a real condition... or an obscure timing bug in emulators.
A way of fixing it is to put a flag that indicates a $2006 2nd write. If this flag is raised on Y-increment, the increment won't occur after PPU cycle 254 (or 255 depending of how you're counting cycles).
I wonder if this is a real condition... or an obscure timing bug in emulators.