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Progress on my Konami M2 Custom RTC Agnostic Bios


Well-known member
Original poster
Top Poster Of Month
May 31, 2019
So I've been sitting on / poking at a project for awhile now, and that's removing the real time clock chip checks out of the revision 2 3DO / Konami bios files so games can boot with a dead / missing RTC chip.

This started because A) screw battery backed volatile memory chips and B) a friend bought a Battle Tryst board from Japan and it came in missing the third sub PCB that houses the RTC board itself.

I've gotten the board booting Total Vice and Polystars with a bios swap, but my end goal is a Dual boot bios (high/low switch on the ROM chip) with the Revision 2 bios bypassing the real time clock checks so games can boot directly into a playable state with a dead battery / missing chip.

Using MAME I've been able to rapidly prototype and test my bios files. What that really means is I've figured out a ton of ways to "hardware error" the game on boot up by messing with the hex values, as so much of the code is obscured. But I am getting there! Here is a "hello world" bios photo for fun :)

If anyone has any thoughts on the matter please let me know. I've got so many bios files for M2 it's quite the task to create a brand new one with that pesky RTC check removed!


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