> mikael
I know exactly why. It's because it's not a regular ROM file. It wasn't designed to be run on an emulator. It was meant to be burned into a BIOS chip and put into a Super UFO Pro 8. You're using it for something it wasn't designed for.
I don't as much about the Super UFO so I'll compare it the DX2 BIOS which is probably similar. The DX2 also has a BIOS. The DX2 BIOS from your ROM in the DX2 won't run on an emulator either. The DX2 has some memory mapping hardware that lets it access both the DX2 BIOS ROM and the game ROM at the same time but SNES emulators don't emulate the DX2 mapping hardware, only the the SNES. Somebody went through and remapped the DX2 ROM so you could run it in ZSNES. An interesting excercise to be sure but have you ever tried to load a game ROM from the GoodSNES DX2 BIOS running on ZSNES? I bet it doesn't work. If you ever try to burn the GoodSNES SMC version of the DX2 BIOS into the ROM chip on your DX2 -- it won't work either.
So, the image I have is straight out of the ROM, dumped by me, gauranteed to be the raw bits. It will work when burned into the ROM chip of a compatible Super UFO Pro 8. It probably won't run on any emulator unless you modify it. See the DX2 BIOS for an example of how to do this.