PS1 - Any way to load alternative BIOS through software?

[bobrocks95]

I'm working on a BIOS patch for the PS1 to allow automatic memory card selection with the MemCard Pro via discs, without requiring a slow UniROM + FreePSXboot or an old model with a parallel port Gameshark unit.

I'm about finished with it but I really don't know of a way to verify functionality on actual hardware short of replacing the BIOS chip, which is what I plan to do once I'm done- but I'd like to be able to do better than cross my fingers and hope it works the first time for testing.

Is there any way, with PS1 dev hardware or otherwise, to load an alternative BIOS image? I'm guessing that you couldn't boot a BIOS file through CD, though it would be great if I'm wrong there (20 coaster CDs is way better than damaging the BIOS pads resoldering to them over and over). If it's possible on dev hardware I could at least attempt to reach out to someone who has the required hardware and see if they'd be willing to try it.

If not, is it possible to socket an SMD chip with the PS1 BIOS' footprint? If so, can anyone point me in the direction of a relatively cheap EEPROM flasher for those purposes? I'd rather not have to buy all that since I can't see myself ever using it again, but maybe I can at least get a knockoff from China to experiment with. It's a 32-pin package on all but some early models, I see an MR27V401E in some photos but I'm sure there's others Sony used throughout the lifespan of the console. Again, no clue if socketing an SMD chip is even a thing.

[ldeveraux]

What an interesting question.while I clearly have no clue, I'm very interested to see you get some help with this!

[bobrocks95]

I did find a potential lead last night with a couple BIOS Flasher programs that can be burned to CD and it looks like reflash the BIOS if you already have a replacement chip in. They didn't make it clear what additional wires need to be hooked up though, I'm guessing a Write Enable and maybe a Chip Select pin.

The original BIOS chip I'm guessing is 100% read-only, though if I remember right there was some older console where you could wire write enable up temporarily to flash its stock BIOS?