TFTP recovery when directly connecting cable not work

Installing and Using OpenWrt Network and Wireless Configuration
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Maybe this can be helpful to someone.

The recovery on a TP-Link C7 V5 was not working by connecting a cable directly from PC to the router. (And doing all configuration to make TFTP work, a good tutorial that I followed is here: https://milankragujevic.com/restore-a-bricked-tp-link-router-with-tftp *)

  • If you use this tutorial, pay attention to the recovery .bin file name, that depends on the model!

After trying hard on Linux and Windows, I did something different.

I connected the router to another router and the computer to that router too. So a router was intermediating the communication between the bricked router and PC.

This middle router was configured to have the IP of 192.168.0.1 .

After configuring my PC to have the target address (192.168.0.66) and the middle router as a gateway (192.168.0.1) I was able to make the bricked router to get the image on my TFTP server.

However, the data transfer was slow and not able to send all firmware in the 5 seconds (the data transfer stopped in the middle). I tried several times, but the maximum I was able to transfer was around 3MB.

So, if someone has a problem to connect directly to the router, this can be a workaround! However, if anyone knows how to solve this transference issue, would be great!

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It is usually better to use an unmanaged switch between tftpd and the bricked router, this prevents the link training during the router reboot (managed switches and even more other routers might need their own link training). The problem is, the tftp window (the time span the bricked device searches for the tftpd or incoming tftp connections) tends to be rather short (1-3 seconds), if the tftp connection hasn't established by then, the opportunity is gone. Rebooting (or powering off the-) router downs all ethernet ports and the connection to your tftp server/ client, establishing it again (the link training, which determines link speed, duplex modes, etc.) can take a pretty while (depending on the bricked router and the ethernet card/ driver on your computer), often longer than the tftp window.

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