Tenda N3 serial pinout diagram

Hello, I have bricked my router (Tenda N3) a while ago. I have checked its motherboard but I can't tell which pins are for RX, TX and GND. Could somebody please tell me which pins would be them?

Motherboard's top
Motherboard's bottom

Thanks in advance

Doesn't look like there is much about Tenda devices on the Tenda pages here or that it is supported by OpenWrt.

At least to my eyes, if there is a serial port there, it isn't immediately evident.

Using Google search I found https://www.techsupportforum.com/forums/f135/tenda-n60-unbrick-968505.html that suggests that at least for one Tenda device there is a TFTP server available.

I just unbricked my Tenda N60 by using a TFTP server. The CFE page did still appear briefly on, but it never worked to upload the correct image. But when doing a tcpdump it is clear that the router was asking who was on So I changed my IP to that, and then it issued a RRQ over UDP on port 69 for a file named vmlinuz.

So I set up a tftp server on that port, and renamed a working firmware image to vmlinuz, and it came up!

Well, I actually figured out yesterday which pins are for GND (TP2) and RX (TP6). The other pins shows only 3.3V. I also wonder if it's possible to cancel the bootloader from loading the FW by just grounding the RX pin. I got a USB to TTL converter and a soldering iron but it would be less painful if that's possible, those pinouts are really tiny. But I'm unable to find out which one would be for TX

These are the sources which helped me find out GND and RX: