PS1 BIOS patch for disc/PSIO Game ID (auto Memcard Pro VMC)

[bobrocks95]

I've released a preliminary version of my patch for PS1 BIOS to send Game ID commands to a Memcard Pro (and possibly an SD2PSX or PS1Digital) for automatic memory card selection from disc or PSIO, like an xStation install supports or if you were to launch games through UniROM. Great for PSOne slims that can't run an xStation and where booting UniROM requires a long memory card exploit.

Details and xdelta patches are available on my github. You will need a replacement BIOS chip that is pre-flashed with the patched BIOS, or a stock BIOS that can be re-flashed with a supplied homebrew program and what should be a 1-wire installation (though I did not have success lifting an individual pin on a TSOP package from a seller with pre-flashed BIOS). I have a handful of extra chips that I may sell pre-flashed to recoup my costs on the flashing hardware I bought, and 2 extra adapter boards from OSHPark I could install 2 of them on, if anyone is interested.

Hardware testing has been minimal so far, so I'd recommend anyone not handy with soldering or with no way to relatively easily re-flash their BIOS to consider caution. There is a socketed PCB adapter option available as the easiest way to rapidly flash your BIOS.

Anyone who does try it out, please let me know if you have any games that do not boot or properly load the Game ID.

If you are confused about what this does, here are two videos from the creator of the adapter PCBs I recommend, mi213:
https://www.youtube.com/watch?v=BJwKBzZzR6Q
https://www.youtube.com/watch?v=0bnTjVvUoDg

[Gunstar]

This is amazing, great job on making this, and thanks for sharing it.

[bobrocks95]

This is amazing, great job on making this, and thanks for sharing it.

Thank you! I wish it was a bit easier to get it installed but I don't want to actively distribute Sony code, and prior to this I didn't really find people swapping BIOS other than to bypass some Japanese consoles' extra region checks.

[Syntax]

No chance on getting this working as an expansion rom?
https://www.psxdev.net/forum/viewtopic.php?t=1319

[bobrocks95]

No chance on getting this working as an expansion rom?
https://www.psxdev.net/forum/viewtopic.php?t=1319

It very well might work as an expansion rom- testing in no$psx actually compiled the assembly and ran it as an expansion rom. I don't have one to test with, but I'll ask if some early users have one.

How hard is it to flash a gameshark/action replay/xplorer cart?

EDIT: It looks to me like the Xplorer FX is the only cart with a 512kB flash chip on it, which is the required size for the PS1 BIOS (nocash's PSX-XBOO is 256kB). If there are any others let me know. I'll look into the flashing .exe that no$psx can generate.

[Syntax]

Sounds very promising!
I do own an FX but can't find it right now.

[bobrocks95]

no$psx unfortunately embeds the rom file in a .exe so its flasher is a no-go. The one I describe in my github the author said to not use it for cheat devices in their original thread.

This might be promising though- https://github.com/danhans42/nxflash

Also in talking with mi213 he may release files for a DIY PCB that plugs into the parallel port with a 512kB flash chip on it.