C8170, tech in field tried to update. After the update it stuck on the splash screen for 3 hours.
He's got it in the shop, on boot, the SBC after a while has a U. showing on the controller.
Tried special altboot, and regular altboot.
Comes up with the same message about 10 seconds into the "upgrade in progress" message.
"Altboot DLM corrupted".
I've reformatted the flash drive, tried a different stick, downloaded the file again, downloaded
the version that is(was) currently on the machine.

SBC? HDD/SSD?