Flashing the Comtrend AR5387un

Set your computer to have a static IP address of 192.168.1.2
See http://ofmodemsandmen.com/static.html for information on how to do this.

Power off the router. Press the reset button near the antenna.
Continue to press this button while powering up the router, which will take
20 seconds or more.

Browse to 192.168.1.1 and use that web GUI to upload the ROOter firmware file.

Wait until the router reboots and then browse to 192.168.1.1 for the ROOter web GUI.