I'm happy to have modified the MM3 source code for 12F629 to work for 12F683 & 12F675! I only own a North American PS1 console so I could only test out the NTSC-U version, though I applied the same changes to the NTSC-J and PAL versions so I'm hoping they will work - but if somebody could test it out and post their results that would be greatly appreciated. I've tested both 12F675 and 12F683 on one PS1 console and both versions worked fine - including stealth. "But wait, doesn't 12F629 and 12F675 use the same code?" Not necessarily, many codes will work on both and produce the same result. However, when I tested out the MM3 12F629 code on 12F675, it would work and boot games, but stealth would not work. This port fixes that problem. The 12F675 port will also function on a 12F629. Compatibility: 12F675 Hex: 12F629, 12F675 12F683 Hex: 12F683 The rar download includes source code and the HEX files, along with the install diagrams for MM3. Obligatory disclaimer: Limited testing was done before release - use at your own risk. Link: http://www.mediafire.com/download/97fh71zbduvfbei/MM3+12F683+12F675.rar Edit: You can also find the Mayumi v4 12F683, 12F629, 12F675 port here: https://www.assemblergames.com/forums/showthread.php?54179-(PS1)-Mayumi-4-0-12F683-12F675-12F629
Small news update: Originally I tested the NTSC-U versions on SCPH-5501, and now I also tested them on SCPH-9001 and it worked flawlessly (including stealth).
Just an FYI .. I tried this code on a 12F675 today.. didn't work. I then burned the original MM3 HEX on a 12F508 and it worked great. I installed it in a PSOne - SCPH-101 (PM-41 2 A)