Hello Giles_Gatineau,
Sounds like you have tried everything already, so it would be a hardware escalation: 1-800-835-6100.
I have issue with my WC6605 so i upgrade to wc6605_FW_201604180657 but i was worth so i downgrade to WC6605_FW_Release_201305012030 and now i have an error in the panel : 016-737 and if i power off power on the printer still to try to download and update ...
any idea ?