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

• Get the firmware and “shorten it”
• Set a TFTP server on your machine
• 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:
  • Unplug power chord
  • Press and hold reset button
  • Power up the device and keep reset button pressed
  • Wait till the lock LED is on
  • 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