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Switchless MCD mod mmmonkey guide - errata

Started by Fix_Metal, September 10, 2013, 08:33:46 am

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Fix_Metal

Hello everybody.
I've got a MCD and a MCD2 lately and gone immediatly for modding them.
I've made every expansion (32X included) switchable via the reset.

As for the MCDs, I've managed to use the 2 standard bios files available on the mmmonkey site (original bios, didn't want the aarakon ;)
There are a few issues I've found:
1) The MCD2 bios file works perfectly. The only thing is to get the correct wiring over the 38/39 pins. I've managed to cut out the old bios (a pair of nail scissors did the job) and put a socket over there.
2) The MCD bios file is wrongly concatenated. The sequence must be USA->PAL->JAP if you don't want to modify the PIC firmware. Seems like the guy did a USA->USA->JAP file. In his guide he inverted PIC/EPROM pins too.

The only thing about using standard bios files, is that the country check is still present. You won't be able to use a different vsync other than the right one for the region at startup, but you can PAL60 later ;)

Fix_Metal

Here's the correct byteswapped MCD1 bios.
It's structured like: usa->jap->pal->jap (E)
The last is useless, you won't ever reach it. Just used it to fill the memory. It's a jap bios that works on pal hardware anyway.