That is the first recorded 'bricking' of a camera by CHDK and definitely the first disaster-recovery !
Wasn't really bricked, luser error.
I wanted to see what factory mode looked like. Turns out, it looks like a brick! But the camera is actually running. Even CHDK was running, but it doesn't display and PTP doesn't load.
But yeah, I'll be a little more cautious before calling random eventprocs.
So
FA.Create registers the factory mode functions.
SetFactoryMode (I think, I tried several) sets something in ROM which indicates factory mode.
ClearFactoryMode undoes the ROM setting. ClearFactoryMode can be called from CHDK spytask with the appropriate wrapper.
Both call WRITEADJTABLETOFROM which I guess does the deed. I wonder if this means my original factory adjustments have been nuked ?
If anyone wants to roll the dice, there's also
SetDurianMode
ClearDurianMode
Durian ?!?