@SilverDeth 620 locations have 0x1b in them and it turns out that the memory map is kind of complicated ( https://www.nesdev.org/wiki/CPU_memory_map ) but if I just guess based on the format having a 16-byte header ( https://www.nesdev.org/wiki/INES#iNES_file_format ) that the 0x1b at 0x98d6 in the ROM is not a coincidence and change it to 0xee (a one-byte NOP, apparently there are lots of NOPs aond some of them ar two bytes: https://www.nesdev.org/wiki/CPU_unofficial_opcodes ) then *this* version runs in at least NEStopia.100.nes