PIC12C508, 12C508A, 12C509, 12C509A, 12F508 and 12F629 are all small 8-pin PIC devices, but “same pinout” does not make them automatically firmware-interchangeable. The 12C5xx/12F508 family and the 12F629 are different devices internally, so the HEX file and wiring diagram need to match the PIC family they were actually written for.

Mayumi 4 - SCPH-7502 / PU-22

MultiMode3 (MM3) - SCPH-750X

Am I missing any models? Send me a message via the contact page and I’ll put a guide together for the particular model and chip you have! :)

Sources