And I assume all of those devices have a UPS
checksum > write > checksum
the failure im referring to is power/other interruptions during the write process. doing a pre and post checksum is worthless if the flash fails half way through.
if its a device that you expect to flash regularly, theres usually a recovery process or failover device, right? no way youre flashing prod devices without a dr or failure recovery.
for a random users keyboard? simple - dont flash it if its not broken.