TL-WR902AC v1 (US) serial recovery

[psherman]

Tried to upgrade my TP-Link TL-WR902AC v1 US to 19.07.0 today and it failed. Not sure why. It is bricked at the moment. I'm hoping to recover it via serial.

Does anyone know where the serial pins are for the TP-Link TL-WR902AC v1 US are? I'm guessing they are on the test points diagonally across from the ethernet port, but I'd love to verify that before I try using them.

This page has pictures of the board, and this image shows the test points in the upper right hand corner (TP1-TP4).

Can anyone confirm that these are the serial ports? And bonus if someone knows the actual mapping of Tx, Rx, and ground.

Thanks!

[juppin]

Hi, why not using the u-boot recovery?
https://openwrt.org/toh/tp-link/tl-wr902ac_v1#recovery

[pepe2k]

@psherman see my commit, I wrote about serial access there: https://git.openwrt.org/?p=openwrt/openwrt.git;a=commit;h=6165e4aab0e22b780b6b1dde887ed803a7c8210a. At least on my version (EU), some resistors were missing on RX/TX lines.

[psherman]

@juppin

Hi, why not using the u-boot recovery?

I had forgotten about this until after my post. Thank you! Worked like a charm, first time. I guess I didn't need to crack open the case

[psherman]

@pepe2k - Thanks! That was the information I was originally seeking and it is very useful to have that info. I ended up taking @juppin's advice to use TFTP recovery (I see that your commit also has the information about the TFTP recovery, as well), and that worked.

Regarding the pinout information, I hope you don't mind me copy/pasting it so that it is directly in this thread for future readers (from your commit page)

UART pads on PCB (TP1 -> TX, TP2 -> RX, TP3 -> GND, TP4 -> 3V3, jumper resitors are missing on TX/RX lines)

[juppin]

Or add it directly to the wiki page