Did you verify the SHA256 hash? Does it match with the one mentioned in the site? If yes, then proceed.
Next steps
- Take a backup of the current device.
- Untick the "Keep settings and retain current configuration"
- Tick the "Force upgrade" and "Continue"
Upgrade Zyxel NBG6616 from 19.07.10 to 22.03.2 (ar71xx to ath79) - #2 by psherman