Hard reset TP-LINK TL-MR3220

Factory reset (Hard reset) Power ON the router. Locate the reset button (or hole) on the rear panel – it should be labeled WPS/RESET or just RESET. Press the button for about 5 seconds – the SYS LED should start blinking faster. When this happens – release the button. If 5 seconds are not enough – try holding the button down for 8 seconds. PS. For older versions of this model you might need a thin object to press into the button hole – try using a paperclip.
Firmware Firmware link
Default username admin
Default password admin
Default IP address 192.168.0.1 or 192.168.1.1