After removing the ribbon cables, take note of the screws holding the motherboard into the main chassis of the camera.
There are two types of screws to remove. The four (2mm, PH00) circled in red have a fat head, and go in the gold contact.
The three (4mm, PH00) screws marked in green have a skinny head.
Use the IFIXIT screwdriver and PH0 bit to remove all the screws holding the motherboard.