Reflashing via Failsafe mode and without USB

Using Python and Linux

If your device is messed up and you are not able to change the network-configuration useful, you may reflash the router, using you local network and a temporary webserver.

In the following HowTo, I assume that you are using an MR3020, but this method works for all routers: you have only to exchange the image(-link). I assume you have a Linux-Computer with a working Python installation.

1. Connect your laptop to the internet.

2. Choose the correct image-file while referring to our hardware list, then open a Terminal and run:

cd /tmp

3. After you have downloaded the image, run the following command to launch a small basic webserver:

Python 2.7:

 python -m SimpleHTTPServer 8000

When this fails (you maybe have Python 3.x):

 python3 -m http.server

4. Then connect to your MR3020 and boot it into failsafe mode

5. Set your computer to the static IP

6. From Terminal, type:


7. Run the following command to download the image onto your MR3020:

 cd /tmp

8. If this worked, flash the image (the exact MTD-command may differ on other hardware) and initiate an immediate reboot if everything was fine (-r)

 mtd -r write openwrt-ar71xx-generic-tl-mr3020-v1-squashfs-factory.bin firmware

Then you have a fresh install. Sometimes something went wrong on the router. Sometimes, I call it: “a bit is switched wrong”, the flash does not work on the first time.. especially if you have a corrupt system. You can recognize that, when your OpenWRT doesn't store your changes- then simply reflash like above.

Hope this helps.

Reflash in Failsafe-Mode using Netcat

Your box gets messed up? Sometimes it is only possible to recover it during failsafe mode. But how can you put the firmware image file to your box?

I read about something called Netcat. The detailed HowTo does not fit well, because the most images lack the server support. After some test, I found out that you can turn it around.

This method works if your computer is Linux. If you don't have Linux as OS, try a live version of it, i.e. grml.

To transfer a file to your router (The following assumes that you already have access via failsafe-mode):

On the computer check what you IP is (command: ifconfig). Then we are starting a Server and pipe the image file into it. After it is done, it will generate a hash-value.

# cat openwrt....bin | nc -l 3333 && md5sum openwrt....bin

(sometimes (on my Gentoo-box it was) the command is)

# cat openwrt....bin | nc -l -p 3333  -X   && md5sum openwrt....bin 

On the router we connect to the Server (on the Router can the filename be shorter, different):

# cd /tmp
# nc 192.168.1.x 3333 > openwrt....bin
# md5sum openwrt....bin

Compare the hash value of both outputs, if they are equal then proceed with flashing.