Well, I have a serial JDM programmer, some PIC 12c508A OTP chips and some hex code for the Multimode 3 and Onechip (from eurasia.nu).
But can I get either of them to work? No!
I'm fairly certain I've figured out how to program them correctly now (using ICProg), but the PSOne I'm using won't boot any discs with the chip installed. Works as normal with the chip removed.
Anybody have any advice?