Thanks for the suggestions. What finally did it, and not even taking the battery out and back in worked, was to switch to CA mode instead of M, and that turned the camera on.
I also pulled the lens off, in the mix, so I'm not sure if that had any effect in reviving it, but at least I'm back in business.
I'd been playing it safe without the autoboot. Guess I'll just wait until there's a .FIR version of RAW working.
Is that even feasible? I know at the moment no such option seems to exist.
Thanks,