UNL-BB Bubble Bobble graphics corruption

[0kmg]

This variant FDS bootleg cart has complete tile corruption that appears after the "Hurry!" message. To observe: play any stage and wait long enough for the message.

I believe the offending line in bb.cpp is: if ((A & 0x9000) == 0x8000)

According to the NESDEV wiki Bubble Bobble should accept register writes from 0xE000 up. The code is picking the else— which is for ProWres—and changes just chr when BB writes to 0xD*** and 0xF***.

(I should note I tested this only in the OpenEmu FCEUX core, but it looks like the same code upstream here.)

[dragon2snow]

realcosole is graphics corruption