Hard reset TP-LINK TL-WA901ND

Factory reset (Hard reset) Power on the router. The reset button is on the rear panel and it is labeled either RESET (for the older models, more ‘square’ look) or WPS/RESET. Press the button and hold until the SYS LED starts flashing more quickly. If your button is labeled only Reset – hold it for around 5 seconds; if it is labeled WPS/RESET – hold it a bit longer – about 8 seconds. The SYS LED is on the front panel – the one that looks like a small sun. You might need to use a thin object to press into the Reset hole.
Firmware Firmware link
Default username admin
Default password admin
Default IP address 192.168.0.254 or 192.168.1.254