I had a few Playstation/PSOne systems laying around that would benefit to having a good old stealth chip. I started looking into the current status of mod chips for the Playstation and it all seems pretty much open sourced not. All the HEX dumps of the major chips are available online and they can be used with a simple $2 PIC. This is just some information I found and will be using this as a spot for notes as I mod a couple Playstation systems.
Many others/variations of the above.
What code for what system?
Fat SCPH-100x = Stealth 2.8a
Fat SCPH-500x-900x = MM3
Slim PSOne 10x = MM3 (PAL model SCPH-102 which should use ONEChip) , Mayumi v5.1
What PIC should I use?
There are actually a few that are proven to work well. I went with SMD ICs since they have a smaller footprint and I always bend or trim the legs on the through hole ones anyways.
I will most likely go with the 12F508 due to cost. I will use the PicKit2 to program the 12F508.