How to upgrade firmware on a Ubiquiti UniFi access point using SSH
1 - Download PuTTY from https://www.putty.org/
2 - Log into your Unifi controller and navigate to Site by clicking on the Settings gear wheel on the bottom left of the controller screen.
4 - The username and password shown above are required for SSH login using PuTTY. Often the password is a series of hexadecimal characters if it wasn’t changed during the initial setup of the controller.
6 - You will be presented with the following dialog box so please read its contents and think about them before clicking Yes as it is a security alert.
7 - The PuTTY window will open, type the username shown in the Enable SSH Authentication screenshot above and press enter.
8 - Type the password shown in the Enable SSH Authentication screenshot in step 3 above and press Enter, ***Please note when typing the password, the cursor doesn’t move***.
9 - Go to www.ui.com/download and find your device by navigating through the list on the left.
10 - Accept the End User License Agreement after reading it.
11- Delete the S from HTTPS as some older devices only recognise HTTP and most newer devices can be upgraded by using HTTP.
***Please note*** if the upgrade fails, you may need to repeat the process without deleting the S from HTTPS.
14 – The Upgrade will begin
16 – The device should now be visible in the controller and the status should be Updating or Adopting.