TP-LINK XN020 - Bricked - what hardware do i need?

I have bricked my XN020, TFTP will not work. I want to attempt to revive it through the serial. What hardware and software do I need to revive my router?

what is the tx and rx pin?

Trial and error, if one doesn't work, the other will, you won't break anything.

You'll a USB TTL, and Putty (win) or screen/minicom (*nix).

Pin 3 is gnd anyway which is pretty unusual!
Pin 1 and 2 seems to have the pull up resistors so they are probably the comm connectors in some order.

And pin 4 seems to be the Vcc with the option for one capacitor.