"Can't open boot device" XO laptop firmware/OFW issue?
quozl at laptop.org
Sun Feb 18 15:55:49 EST 2018
As it ages, the microSD card takes longer and longer to erase and
Eventually the time it takes to erase and write may exceed the few
seconds between end of reflashing and the reboot power cycle.
In those situations, use fs-update instead of the four button method,
and leave the system on for five minutes before the first reboot.
More information about the Devel