Debrick TP Link Archer C2

[Untrue]

Hey guys, what's up.

Okay, so after a possible bad flash via tftpd, the router doesn't go into "recovery" mode anymore, so that option's closed.
able. Thing is, router doesn't respond. I don't really know what I'm doing wrong or how I can check if everything is alright. Putty doesn't show any signs of life.

Maybe I am using the wrong pins. I tested with a multimeter and from left to right it gave this:
3.3V 0V 0V 3.3V

I assumed the left one was VCC so I didn't solder a pin onto it.

[jeff]

Do you get any LED activity when you try to boot the device?

TP-Link Archer C2 AC750

ethernet ← VCC GND TxD RxD → Leds

On some versions you need to solder 2 bridges to get serial port working. You need good soldering experiences for that!

[Untrue]

Does that mean I pinned it correctly?

Power led stays on. Internet led powers on then dies.

I don't know which bridges to solder, really. Wish I knew.

[jeff]

@Untrue

Power led stays on. Internet led powers on then dies.

That potentially means that the boot loader is running.

I don't have a C2, but looking at the back side of the board from the images on the ToH

and knowing TP-Link's penchant for not populating things, I would guess, and purely guess that certain units may not have one or more of R54, R137, R500, R601 unpopulated. That you've got 3.3 V on the RX pin suggests that it, at least, is connected and has a pull up to +3.3 V (assuming that you checked without the adapter connected).

[Untrue]

I'm sorry, I'm a total noob when it comes to electronics. I wouldn't know what this means. I'd love to understand, though.

[Untrue]

Okay, so I did a loopback test on the USB TTL cable I've got here (one of these https://images-na.ssl-images-amazon.com/images/I/41V6wBUKLXL._SX466_.jpg) and everything went well. So it's not that.

I still can't access the router through the serial port. I tried everything. Maybe it's toast? Maybe flash is not working properly (I don't have the tools to check it).

[jeff]

If that used 5 V logic, it is possible that the serial port of the SoC or more has been damaged.

Does your board have the four resistors in the places shown in the image above?

[Untrue]

It does have those four resistors. Here, a pic of my bad soldering skills and the four resistors:

[Untrue]

For all that matters, I'm using this guy:

I don't know if it's the right tool. It worked with my WRT1200AC.

[Untrue]

No ideas?

I refuse to think that it died because of my soldering or because of a bad flash.

[martin.ka]

Hi, I have the same problem as the Untrue: after unsuccessful firmware flash vi FTPD the router is not able to go into recovery mode anymore. It only lights the Power led with a short blink of the internet led. After the connection tpo serial port with Putty & UART CP2102, I got only weird symbols. The voltage on pins is 3,3V - 0 - 0 - 3.3V. Any idea of how to proceed? Thanks.

[orangepizza]

if you messed up on tftp flash of archer c2, it will overwrite the bootloader, make it unable to boot
no serial cable will fix it, you will have to a clip cable to directly read memory to write a right image dump on it: but I think buying a new router may be cheaper than eeprom writer that needed.

[martin.ka]

Thanks, for your reply. I tried my luck with EEPROM programmer: unsoldered the chip, flashed it by an image found on another forum and soldered back. Everything went well and the router works again.