For anyone curious here is both variants of PS2 backwards compatible motherboards. Top is full BC, bottom is hybrid BC : r/PS3
Motherboard/ Mainboard for Fat Playstation 3 PS3 20g/40g/60g/80g (Pulled) (WRP3053) - China for Ps3 Mother Board and for Ps3 Main Board price
PlayStation 3 Motherboard Replacement - iFixit Repair Guide
Placa madre Sony PlayStation 3 PS3 VER-001 - CECH-L01 - problemas de sobrecalentamiento | eBay
For ps3 fat motherboard SEM 001 with logic board CECHG04 40gb for ps3 fat console|motherboard btx|motherboard hp pavilion dv9000motherboard sale - AliExpress
FW3.55 DIA 001 Motherboard for PS3 fat Game Console|motherboard satellite| motherboard chinamotherboard - AliExpress