Just to add: If one of you finds a way to recover a device where the whole internal flash is messed up, i.e. no bootloader & friends... just let us know
It should be possible to do that via sd recovery, but I am not sure if there needs to be a boot loader or something on the internal flash to get sd recovery working....
E.g. if you have a spare T1 or lot's of money to waste one or a broken one with cracked display and lost warranty but working USB access... try to dd if=/dev/null the internal flash and then boot a sd recovery image....