PS2 BIOS Chip Swapping

As the blog title says this blog gives info on swapping BIOS chips between different PS2 motherboard revisions.

TOOL:

I didn't want to use a heat gun on the motherboard so I built my own tool to heat up both sides of the BIOS chip legs at the same time. It consists of a broom handle end, two small copper squares, a bolt and a few nuts. I flooded the bios chip legs both sides with solder. Heated my tool on the gas stove then placed my tool on the BIOS chip then dragged it off.

RESULTS

Confirmed Working: 

1. Putting a BIOS chip from a SCPH-79002 motherboard with a date code of 7D onto a non-FMCB exploitable SCPH-90002 with a date code of 8D to enable FMCB functionality.
2. Putting a BIOS chip from a SCPH-90002 motherboard with a date code of 8B onto a non-FMCB exploitable SCPH-90002 motherboard with a date code of 0C to enable FMCB functionality.
3. Putting a BIOS chip from a SCPH-90002 motherboard with a date code of 8D onto SCPH-90002 motherboard with a date code of 8C.
4. Putting a BIOS chip from a SCPH-90002 motherboard with a date code of 8? onto SCPH-79002 motherboard with a date code of 7C.

Partially Working - With Issues: 

1. Putting a BIOS chip from a fat SCPH-50002 model GH-026 motherboard onto a slim PS2 SCPH-70002 GH-032 motherboard to enable FHDB functionality on a soldered IDE modded PS2. The PS2 can boot FHDB prepared HDDs without the need of FMCB prepared memory cards. Untested but discs might not be discover-able. See note below.
   
2. Putting a BIOS chip from a PAL SCPH-50002 GH-026 motherboard onto NTSC-J SCPH-50000 GH-029 motherboard with a date code of 8C. Changes the language selection options to the PAL ones meaning returns X and O buttons to their common actions, X=enter, O=back. Issue breaks dvd player.
3. Putting a BIOS chip from a PAL SCPH-70002 GH-032 motherboard onto NTSC-J SCPH-70000 GH-035 motherboard. Changes the language selection options to the PAL ones meaning returns X and O buttons to their common actions, X=enter, O=back. Even though GH-035 motherboards have a few extra voltages due to the combined EE+GS, GH-032 motherboards BIOS still have that data to output those voltages which still allows the PS2 to run.

NOTE: Swapping BIOS chips between different PS2 models may result in discs not reading because of firmware differences between the BIOS and the mechacon IC.

NOTE: Swapping BIOS chips between different region PS2s does not get around the game discs region lock as that is enforced by the firmware inside the mechacon IC.

Not Working:

1. Putting a BIOS chip from a fat SCPH-50002 model GH-026 motherboard onto a slim PS2 SCPH-70002 with a GH-035 motherboard. Boots to a black screen only