We are working on solution where end user can reset their devices back to factory state, even if they have managed to get their devices filesystem in non bootable state (as long as btrfs works). That will most likely happen with custom recovery mode which will be installed at some coming update. More info will be available next year.

We are also investigating if we can offer real flashing solution without breaking device security, but for now the approach will most likely be to update recovery image which will allow resetting back to factory state (after querying devicelock code if that has been set).