Refurbed Fairphone 4 purchase. Returning to default OS

If you want to lock the bootloader, I would advise you to flash the OS again (technically you only need the frp partition) so that “fastboot flashing get_unlock_ability” returns 1. Then, do “fastboot flashing lock_critical”, keep Volume Down pressed while confirming to reboot into the bootloader and finally do “fastboot flashing lock”. That way, you should be safe from bricks.

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