Trained professionals only!

Managed to brick an engine ECU on a customers forklift truck earlier this year during a software flash. Got a new ECU, but flashing it resulted in the same failure. A lot of cursing and trail-and-error resulted in the conclusion that the power supply to the ECU was interrupted during programming.

So I tricked the power supply by bridging a relay and feeding the ECU directly from the battery. Successful!