Does anyone have experience with Famicom Jump 2 (CRC: 3F15D20D? My ROM was actually mapped to mapper 16 but with some header overrides ala NEstopia), I set this ROM to run on mapper 153 (LZ93D50 with SRAM). I suspect the problem is the outer bank register in the range $8000-$8003, which allows the programmer to switch to the upper 256K of PRG rom.
My logic is that if a byte value set in any of the four addresses $8000, $8001, $8002, $8003 has the lower bit set (value & 0x01 != 0), then $40000 is added to the PRG banked address. Is this logic correct? The code seems to set different values across the 4 addresses so I'm thinking I got it all wrong.
My logic is that if a byte value set in any of the four addresses $8000, $8001, $8002, $8003 has the lower bit set (value & 0x01 != 0), then $40000 is added to the PRG banked address. Is this logic correct? The code seems to set different values across the 4 addresses so I'm thinking I got it all wrong.