If you have a TP-Link WR840N v6.20 (note it’s v6.20, this will not work for v6, or other versions!) and want to flash firmware, you probably noticed that the traditional method of striping TP-Link bootloader from the firmware does not work with this model. However, it is actually very simple to flash new firmware, if you know the proper command.

  1. First, go to Official TP-Link site to download the latest stock firmware image (at time of writing, that is TL-WR840N(EU)_V6.20_180614.
  2. Unpack the firmware image and locate the bin file. Rename it “original_firmware.bin”.
  3. Obtain the dd command. On Linux it’s built in, but on Windows you have to download it from here. Copy it to the folder with the firmware.
  4. Run the following command, which will strip the first 512 bytes from the firmware image and create a new file called tp_recovery.bin: dd if=original_firmware.bin of=tp_recovery.bin bs=512 skip=1
  5. Obtain tftpd64, which you can find here.
  6. Extract the tftpd files into the folder with the firmware. But don’t run it yet.
  7. Turn off WiFi on your computer, if you have it. Then, go into Network Adapter settings, and set Static IP for Ethernet to 192.168.0.66.
  8. Unplug all cables from the router except one ethernet cable, which you need to connect to the computer.
  9. Launch tftpd64
  10. Hold the WPS/Reset button on the router and at the same time plug it into power. Keep holding the button until a progress bar appears in the TFTPD64 window.
  11. The router will be flashed. You can release the reset button and wait a few minutes for it to boot. Check if everything is okay by visiting http://192.168.0.1/.

Congratulations, you have recovered your TP-Link WR840N v6.20 router!