First, download and save the firmware your computer.

Next, log into the router (http://192.168.0.1)

Click on "Network Settings" (cogwheel button).

Click on "Tools" and then "Firmware" from the left hand menu.

Click on the “Choose File” button and navigate to the location where you saved the firmware.

Click "Open" and then "Apply" to update the firmware.

Wait until firmware uploaded successfully