Hazel

Before upgrading:
☑ Please double check the downloaded firmware version before upgrading. RT-AC is not suitable for RT-AX or vice versa.
☑ Unmount your USB drive from the UI. Otherwise physically remove it and reboot before trying again. Sometimes it takes a few tries. Be patient, that router ain't going nowhere.
☑ Please DO NOT ATTEMPT to update your router in Restoration or Rescue Mode as you'll most likely will be one of the few who manages to brick an ASUS Router if you missed the first ☑