The following procedure works only on the V1 model. Please, don't try this on any other revision. You can check which version your C2 is by looking at the bottom of it or, in the router's web interface, Status page, Hardware Version information, if you are using stock firmware.
As per the instructions in the git commit adding support for the Archer C2 AC750 v1, you need an OpenWrt image with integrated bootloader when flashing through TFTP (TP-Link pretty much always has the bootloader integrated in their firmwares).
OpenWrt 19.07.1 can be flashed via TFTP using an unofficial recovery image provided here; however, if you are familiar with the command line and have access to a Linux box, it's recommended you build such an image yourself, as you'll be able to use the latest OpenWrt stable release. See instructions below.
Creating an OpenWrt TFTP recovery image
If you feel uncomfortable doing this, grab the prepped 19.07.1 image linked to above and skip this section.
The C2v1 TFTP recovery overwrites the uboot partition, hence it must be included in a recovery.bin
An official stock TPLink firmware file has a 512 byte header, which needs to be stripped for TFTP.
You need access to a Linux box for this procedure (Windows Subsystem for Linux ('WSL') might work as well).
Instructions below are taken from the git commit that added support into OpenWrt.
Set your computer's IP to a static 192.168.0.66 address (subnet mask 255.255.255.0 and default gateway to 192.168.0.1).
To flash the recovery image, start a TFTP server from IP address 192.168.0.66 and serve the recovery image named 'ArcherC2V1_tp_recovery.bin'.
Connect your device to the LAN port, then press the WPS/Reset button and power it up. Keep pressing the WPS/Reset button for 10 seconds
The device will try to download the recovery image and flash it. This might take up to 20-25 minutes to finish. When done, the router will reboot itself.
After reboot, you can access OpenWrt at 192.168.1.1. From here on out, you can simply use sysupgrade with the vanilla OpenWrt images to upgrade.
If you encounter timeouts, you might want to put a switch between your router and client to facilitate the flashing process. The tips below might not be needed after that.
A few users reported that flashing via TFTP server was only possible when the option “Use anticipation window of” with 1000 bytes was enabled in TFTPD32 for Windows. So, if your flashing process hang at some point, restart the process with this option enabled.
Also, you might have to lower your ethernet link to 10 Mbps Half Duplex in order to finish the process.
Similar instructions can be found as posted by OpenWrt forum member yoqhere. Old recovery image c2_recovery.zip can be downloaded here.
The case is a bit hard to open, start with the two screws. Then start prying the lid from the bottom of the case, starting at the side with the ethernet connectors, There are 11 notches all around keeping the lid in place. They come loose by pushing the bottom part of the case outward.
Serial port: TTL voltage, 115200 bps, 8N1.
At least one user has reported 3.3 V logic levels, not TTL (5 V) levels
The Serial connector is labeled 'J2', and is wired as follows:
Ethernet side of PCB
VCC ... not used.
GND -------------- GND of Serial adapter
RX <-- input <-- Tx of Serial adapter
TX --> output --> Rx of Serial adapter
Led side of PCB
Where 'RX' connects to the output of your serial adapter, and TX, connects to the input of your serial adapter.
You can verify this, by using a volt meter to check that 'TX' pin is at Vcc level, and the RX pin is at GND level.
The GND pin may be a bit hard to solder, i needed to scratch away some paint from the PCB to make a large enough connection.
On some versions you need to solder 2 bridges to get serial port working. You need good soldering experiences for that!
The bootloader of the stock firmware can be interrupted by pressing a digit from 1 .. 7, press '4' for the u-boot prompt.
From the serial console, you can login to the running linux of a stock firmware with: username 'admin' and password '1234'.
The C2 uses a external GBit switch, connected by MDIO bus. Network traffic to the CPU is passed through the internal switch of the MT7620A SoC:
toh/tp-link/archer_c2_ac750.txt · Last modified: 2020/04/12 14:12 by borromini