You're going to have a lot of fun with that.
First, you need to modify MAME to NOT demand strict checksum matches for chd files. By default MAME won't run modified ROMs. I do not know if this is merely a configuration option or if it requires recompiling MAME.
Second, you will need to convert the CHD to a raw file. There's a MAME tool for this; if you build from source you need to pass a special argument to make to build this. I forget what the tool is called.
Once you get the raw file, which should be a GD-ROM image, you will need to edit the GD-ROM. Hopefully NAOMI GD-ROMs don't have additional requirements or changes from Dreamcast GD-ROMs! (This seems to be hit-and-miss; Puyo Puyo Fever seems to have a nonstandard disk layout...)
And that assumes Monkey Ball doesn't do its own integrity checks. If so, you'll need to go into the code sector and disable those, too. (I do not know if the SH-4 in the NAOMI is big endian or little endian but if it's the same endianness as the 32X's SH-2 then IIRC 00 0B / 00 09 is rts/nop - yes you're going to have to deal with branch delay slots!)
Then you have to hope you can repack the GD-ROM and CHD properly before giving it back to MAME.
If a normal Dreamcast emulator supports booting NAOMI raw GDR-ROMs you would probably have an easier time doing that instead. |