Update Unifi AP using SSH

Download the correct software from Ubiquiti.

Change the name from the downloaded file to fwupdate.bin

Open WinSCP and connect to the AP using SCP protocol.

Copy the fwupdate.bin file to /tmp folder.

Close WinSCP and open Putty. Connect to the AP using ssh.

Issue the command syswrapper.sh upgrade2 & after this your session will close automatic and the AP will start the upgrade.