TP-WR841N[D]

TP-WR841N and TP-WR841ND is one and the same model, except TP-WR841ND has detachable antennas.

Specs

DO NOT BUY v13!!! V13 contains a mediatek chipset, which requires a non-free firmware blob.

Flashing instructions listed below were tested with TP-WR841N ver 8, with original firmware version 3.13.33.

Reset to factory default state (don't really know if it's required, but definitely won't do any harm).
Go to 192.168.0.1 and login with default credentials (admin/admin)
Navigate to System Tools -> Firmware Upgrade and provide factory bin file. Press Upgrade to perform flash.
After router is flashed and restarted make sure to stop NetworkManager service (might not be required, but I couldn't access libreCMC web interface without stopping it).
Go to 192.168.10.1 and login with default credentials (root/root).
Navigate to System-> Backup/Flash Firmware and in "Flash new firmware image" section provide sysupgrade bin file. Press Flash image to perform flash.
After successfull flash NetworkManager can be started again.