I tried flashing TP-Link Archer C2 AC750 through TFTP but it bricked the router.

Now it is like this :

When I switch ON the router, POWER LED and INTERNET LED will glow.
INTERNET LED switches OFF immediately and Power LED remains ON.

Nothing else is working. When I connect the LAN cable to my PC, it detects an UNDEFINED NETWORK.

NO IPs, NO Pings..

TFTP is NOT WORKING now.

Please help me for Debricking it.

C20i has a bug in bootloader which causes similar problem.

In C20i, its TFTP recovery mode needs image containing not only firmware, but also the bootloader (U-Boot), because it erases FLASH chip from address 0x0 (where bootloader image should be placed):

[...]
Bytes transferred = 7995392 (7a0000 hex)
NetBootFileXferSize= 007a0000
 Erase flash !!
From 0x0 length 0x7C0000
raspi_erase: offs:0 len:7c0000
[...]

So, if the same bug (you can call it a feature as well...) exists in C2 then you have serious problem - the only way to repair your router is to program FLASH chip using external SPI NOR FLASH programmer.

:-(

I checked the PCB of C2, but I can find only UART serial port. Where to connect external SPI NOR FLASH programmer ?

If you've not already done so, I'd suggest hooking up a serial console so you can see what's going on - I think it's much more likely something that'll be easy to fix once you can see what's going on

Hopefully this post will help, it's got some useful issue from when I thought I'd bricked mine last year - I only which I'd had a decent cable when I had issues with my previous router, my dodgy soldering job did for that one

The serial console detail are in the wiki, but I don't think it covers the jtag details, which I'm hoping won't be needed anyway

If you only need pure serial (TTY / UART) i recommend you FTDI FT232RL (around $2.50 on ebay incl. shipping), and for SPI flashing, Raspberry Pi (price without VAT and shipping depends on model 20-35$) with Flashrom can handle this stuff, also UART and I2C, even JTAG via GPIO Bit-Banging using OpenOCD.

EDIT: FT4232H - quad channel UART and BitBang with 2 Channels also possible SPI, JTAG and I2C. (around 25$ on ebay)

(Last edited by Snoop05 on 21 Oct 2015, 19:49)

I am not getting anything on my Serial Console. I used baud rate 15200.

I think the bootloader is corrupted. Please help me.

You should use 57600.

57600 is not working, :-(

So, if you are 100% sure about connection, then that means you need to reprogram FLASH memory (remove it from PCB, put in some external FLASH programmer, program new image and solder it back on PCB).

What image did you use to flash the router? I wasn't aware of any release for this router.

This one : https://wiki.openwrt.org/toh/tp-link/archer-c20i

It mentions that TP-Link Archer C2 AC750 links to that page.

as i can see C2 uses simple 25Q64 winbond flash chip which can be programmed by CH341A based 3$ USB programmer
also you can order sop8 clip to flash it without unsoldering

Dear stas2z,
Thanks for the information.

Can I write *.img image directly using it ?

not exactly, probably you need to cut a header of original image
or you can flash only uboot by programmer keeping other data untouched and flash original image from uboot tftp recovery mode

It's highly not recommended. With clip you will provide power to not only FLASH chip, but also other components on the board.
What's more, FWIK, this MediaTek chip doesn't have HiZ GPIOs.

@pepe2k
yep, powering device through the flash chip is not a good idea, but in case of no or low soldering skills its better than damaging pcb
unsoldering only vcc pin instead of whole chip and using clip is a good solution, it's easier and safe

The problem is that, it's not safe. In worse case, you will damage something on board with your approach.

@pepe2k
it's almost impossible to damage something by powering flash chip on the board (if you are connecting it right)
but powering chip can cause powering whole device (which will try to boot) and writing to flash when device is continuously rebooting is not a safe way (but you still have a big chance for successful flashing)
unsoldering flash chip vcc pin from pcb before flashing pin will isolate usb power circuit from device power circuit at all

(Last edited by stas2z on 8 Dec 2015, 17:19)

Just an example - not all DC/DC converters and LDO chips like to get voltage on their outputs, without powering their inputs.

Again, this MediaTek doesn't have HiZ I/O. If you disconnect VCC FLASH pin from board, current will flow to the board over SPI I/O pins and the SOC.

Can I use openwrt or original router firmware as such while flashing directly to that spi flash chip ? OR should I include bootloader along with it ?