TP-Link TL-WR740N is one of the cheapest and feature-packed router available in the market. With the price tag of 12.99$, it is definitely worth a buy.
If you’re an owner of WR740N, you ought to exploit its DD-WRT or OpenWRT support, for features such as Repeater, OpenVPN etc With the price, it’s of low harm to try Custom Firmwares and tinker around with the router, and with the method I am providing in this article it becomes totally lossless even if you brick your router upon trying different firmwares.
So I tried DD-WRT, Stock -> DD-WRT and then OpenWRT, DD-WRT -> OpenWRT. But in my journey back to stock, OpenWRT->Stock, the router got bricked. I had following signs to believe that it is now bricked and is not usable:
- Only the Power LED lights up.
- GUI based interfaces won’t work (e.g 192.168.0.1 or 192.168.1.1 or tplinkogin.net)
- PuTTY won’t find a communication to the router.
- Telnet won’t work.
- WinSCP can’t connect to the SCP server on router.
Hence, in short, the router is gone. The methods available needs a Serial cable to access the flash memory, a lot of tinkering around with the hardware and a possible chances of messing up if you’re not a hardware pro. After a lot of research, I found out that TP Link has provided a default anti-brick method to let users flash a firmware even when the router is bricked. Let’s see how to work with it.
Things you’ll need:
- A bricked router with at least one of the signs from above list.
- A TFTP Server (Download TFTPD32 here).
- A firmware file ( Get stock firmware(preferable) here or OpenWRT here, or DD-WRT here).
- A working brain.
Disconnect router’s LAN cable from PC, Turn of the router.
- Step 1:
Change your network IP address to 192.168.0.66 and subnet mask to 255.255.255.0 (In Windows 7, Goto Control Panel > Network And Sharing > Change Adapter Setting > Right-Click on you Ethernet adapter > Properties > IPv4 )
- Step 2:
Rename the downloaded firmware file to wr740v4_tp_recovery.bin.
Start Tftpd32, ‘Browse’ the current directory to the folder where wr740v4_tp_recovery.bin is stored.
- Step 3:
Put a pen/pencil in the reset button hole behind the router, and turn it on (while still holding the reset button).
A few moments after the router is turned on, you’ll see the Lock LED has lit up, release the reset button.
- Step 4:
Now connect the router LAN cable to computer, you’ll see Tftpd transferring firmware files to the router. Wait for the router to automitically flash the firmware file using the built-in tool and reboot itself, the entire process should take around a minute.
That’s it. Once the router reboots, you can access the interface that is provided by the firmware. 🙂
For explorers who wants to know how it works:
The router looks for flash files when it is started in safe mode (The Lock LED?) it looks for files on computer in the IP range from 192.168.0.2 to 192.168.0.68, i.e. total 66 ranges. Now our TFTP hero, the Tftpd server, serves the files using the default network interface which we IPed as 192.168.0.66. The router requests for files on the IP, and Tftpd transfers them to the router. The router then, flashes it and reboots. Eliminating the need of using serial cables or JTAG to flash the memory manually.