I replaced the SMC on an 820-3437 and the board works fine, however it won't boot into the customer's OS. I verified that their drive does boot on another machine. I suspect the issue is that the SMC firmware on the SMC I put on is too new for her OS (Mountain Lion) or maybe vise-versa. Unfortunately I cannot do a complete reinstall of their OS as they don't have it backed up.
Is it possible to downgrade the firmware on the SMC from another OS, and if so, what version/does anybody have a link to the SMC firmware?
Is it possible to downgrade the firmware on the SMC from another OS, and if so, what version/does anybody have a link to the SMC firmware?