vanduino:
(Now... what to do with these bricked Megas?)
I think they should be sent back to the vendor with a warranty replacement request. The vendors get away with a lot that wouldn't be tolerated in consumer products under the umbrella 'electronic hobbyists'. And in this case I think that replacements are justified. I hope to do this as soon as I have a talk with my customer, who purchased the boards I used in development. My usage of the boards falls within all the documented specifications, and there are no caveats mentioned about usb and external power. If distributors start getting boards back then that drives change at the manufacturing level.