How can I upgrade the firmware by using FTP?

Zyxel_Charlie

You can access the device by using a console and enable FTP on the USG.

On your PC, use CLI commands to access the USG by FTP. 

Set the binary and add the file.(paste the path of bin file)

After clicking Enter, the firmware starts to upgrade.

VERIFICATION:

If the configuration is correct, you will see the “Transfer complete” message when the upgrade finishes.