Hi, if you want to reinstall the firmware back on the OpenWRT router you can follow this guide.

1. First, download the firmware from the official website. Please find the correct image matches your router’s hardware version and the region you are in. In my case, I downloaded this http://www.tp-link.com/sg/download/TL-WR841N_V11.html#Firmware. Unzip the file and find the bin image there.
2. Rename the bin image as wr841nv11_tp_recovery.bin.
3. Download the WinSCP software for Windows.
4. Open the WinSCP app -> It will prompt to add the remote location.  Select SCP as the file protocol –> give the hostname of router (e.g. 192.168.1.1), keep the port as same, the username of the OpenWRT enabled router is ‘root’ —> Click ‘log in’.
5. It will authenticate and prompt to trust the certificate. Click OK.
6. You can then dig into the directory tree of the remote server, in the left side of the user interface.
7. You can select a file from the right side (your computer) to copy to the remote server. Select the stock image of the TP-link router.
8. Right-click on the image (e.g. wr841nv11_tp_recovery.bin) –> upload–> select the destination directory at the remote server (e.g. /root/tmp)–> OK. File transferring is all done now.

Upgrade the firmware on OpenWRT device.

• Plug the router into the Linux machine using an ethernet cable.
• Open terminal and connect to the device using the following commands

ssh root@192.168.1.1
cd /tmp
sysupgrade -F -n -v wr841nv11_tp_recovery.bin

Thanks !!! 🙂