How do I reset the EX6120 to factory default settings?

You can reset the extender using the Factory Reset button on the side panel by inserting a straightened paper clip into the button hole and holding it for about seven seconds until the Power LED lights amber, then releasing it. Alternatively, you can log in to www.mywifiext.net, go to Settings > Other Settings, and click the RESET button. Both methods will erase all configured settings and take about one minute to complete.