MS2 1/2 boot...

[channelmaniac]

Yes,

It's a half boot. The guy I got it from took a bootleg cart and a real cart apart and swapped the boards to get a working one.

I have a PROGBK1 with real mask ROMs for the audio and EPROMs for the program ROMs. It now works as the mask program ROMs were bad.

The video ROMs on the boot board are a nightmare though. The real MS2 uses 4 64mbit ROMs while this board is a CHA256B with 8 32mbit ROMs. The problem is that I haven't figured out how they are splitting the images up from 4 big to 8 smaller capacity ROMs.

Anyone have ideas on that?

Thanks!

Raymond

 

[shadowkn55]

There are two versions of MS2 CHA boards. One of them is CHA512 with 64mbit roms and the other is CHA256 with 32mbit roms. The roms are split in half with no byte swapping or anything.

C1 (64mbit) -> C1 (32mbit), C3 (32mbit)
C3 (64mbit) -> C5 (32mbit), C7 (32mbit)

C2 (64mbit) -> C2 (32mbit), C4 (32mbit)
C4 (64mbit) -> C6 (32mbit), C8 (32mbit)

 

[channelmaniac]

So lower half of C1 in the MAME dump goes in C1 and the upper half in C3? Sounds simple enough.

Thanks!