OpenWrt Forum Archive

Topic: Bricked TP Link wr340g

The content of this topic has been archived on 26 Apr 2018. There are no obvious gaps in this topic, but there may still be some posts missing at the end.

I bricked my router yesterday and wanted to know if anyone of you knows the pins in the router board to connect the serial cable and reinstal the firmware.Thank you.

Here is your router: I think. The four pins in a white box on the top left corner near the black rectangles right under the reset button are the serial pins (note: in the picture there are header pins soldered on already.)  This is probably 1 - TX, 2 - RX, 3 - GND, 4 - VCC. pin 1 is the one with a square around it. this is not you router but the same idea:

Firesam,thank you for your answer.Actualy my router is this  and maybe the pins are in the red box that I made.

(Last edited by timiog on 14 Feb 2014, 18:43)

The pins are in the red box, and the pinout seems to be the same (maybe Tx and Rx are switched, but that doesn't hurt).

remember not to use vcc if you are using a self-powered serial interface.
router takes its power from its ac adapter.

Thank you both,do you know which is the best and simplest cable that I can make myself to use it?

Thank you nebbia,thank you all.

Any result ? Seems that bootloader is locked with password. Any info about your unbricking ?

The marked with red should be your serial. You need a multimeter. First find the ground pin. Then find the VCC pin - you should get 3.3V/5V (not sure). The other two pins are the RX and TX.
You can use any 3.3V TTL cable (I use Nokia CA42 cable - i soldered pins on it). You can solder pins to your router and use jumper cables to connect to the TTL adapter. You can find cheap 3.3V TTL adapters on ebay@~$2. They have pin header smile

For other routers I have put 3.5mm stereo female jack and have soldered the male another CA42 cable.
CA42 uses PL2303 chips.


Have you managed to get this working? I get nothing on the serial console.
Also the pins are marked J1 and not JS1. Maybe this is not a serial interface. The VCC and GND ports seem to be working. I get 3.3V on them.

I have the WR340G v4.
And I am using this serial cable:

(Last edited by crazyquark on 29 Sep 2014, 09:10)

OK, I have figured out.

I'll post this info here in case anyone needs it.
The wr340g (v4 here) has the same pin layout as the wr741N.
The serial console is activated by running a wire from the TX pin to the pin on the Atheros chip.
The info is here: …
Specifically, look for the v4 info.

And this is the wire you have to solder on the back of the PCB: … tl-wr741nd

The serial console is not password protected. You get a limited list of commands that seem useful enough.
At the beginning you will get a chance to hit ctrl-c and ask the bootloader to load a different image(via TFTP I think).

I got my info from this russian forum:

(Last edited by crazyquark on 1 Oct 2014, 10:15)

The discussion might have continued from here.