Hard reset TP-LINK TL-MR3040

Factory reset (Hard reset) Power on your device. Locate the reset button – it is a hole labeled ‘reset’ next to the USB port of the device. Press in it with a pin or paperclip and hold for at least 10 seconds. Then release and wait a minute or two while the router goes back to its factory defaults.
Firmware Firmware link
Default username admin
Default password admin
Default IP address