How do I restore the ECB5240M to Factory Defaults?

Method 1: Press and hold the reset button for 10 - 15 seconds, then release. The device will reset and reboot to factory defaults. 

Method 2: Log into the device, click on "Advanced Setup", click on "Factory Defaults", and click on the "Restore Default Settings" button next to "Factory Default setting". The device will reset and reboot to factory defaults