This router is a TL-WR702N.  I've been using it for several years in client mode providing connectivity to WiFi netork for a Star Micronics TSP640 receipt printer.  Now the WR702N has become unresponsive and the printer will not connect to the WiFi network.  I have reset to factory defaults.  After 7-10 connection attempts, I get login prompt in browser.  After another 7-10 attempts, the status page loads.  Changing pages takes multiple clicks on the menu links.  

Has anyone encountered this?  

I have tried connecting via SSH to try erasing the NVRAM and rebooting.

Is there another way to erase the NVRAM?

Is there something else I should be looking for?