How to reset (recover) the factory firmware on a TP-Link TL-WR842ND v2.1.

1. Get the firmware and “shorten it”
2. Set a TFTP server on your machine
3. Put the device on failsafe mode and connect to computer static IP: 192.168.0.66

All info is taken from this page on OpenWRT and corrected to work with my particular device and setup.

• Download latest firmware from here: https://www.tp-link.com/us/support/download/tl-wr842nd/#Firmware
• Since it's a “boot” version, you need to “shorten” it (and rename it)

dd if=wr842ndv2_en_3_16_9_up_boot(150514).bin of=wr842nv2_tp_recovery.bin skip=257 bs=512

On Arch:

pacman -Syu tftp-hpa

Then move the wr842nv2_tp_recovery.bin you just created and put it in /srv/tftp.

Start the TFTP server:

systemctl start tftpd.socket
systemctl start tftpd.service

• Correct a good RJ45 cable from LAN on the device to Ethernet plug on computer configured as static IP: 192.168.0.66
• Put device in failsafe mode:
  1. Unplug power chord
  2. Press and hold reset button
  3. Power up the device and keep reset button pressed
  4. Wait till the lock LED is on
  5. Release reset button

If all goes well, the device should pick up quickly the new firmware and reboot.

— Julien Deswaef 2021/04/17 20:46