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!
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!
