How to Unbrick a TPLink MR3420 Router?
Yes, my bad luck on routers continues! However, this is good news as this is a router revival post.
So here’s my story…
Currently, we are using a TP Link MR3420 with USB Dongle for our internet connection. It was a day that I felt adventurous and I tried to flash a custom firmware (openwrt) to the router. The instructions were easy as I just followed it from this wiki
After a few minutes, my router was reborn with a new firmware however there was just one problem. My USB dongle doesn’t work anymore so in panic, I decided to re-flash the original firmware from the TP Link site.
V2 – http://www.tp-link.com/ph/download/TL-MR3420_V2.html
and that became the fatal decision. The install failed but the damage has been done. By flashing the original firmware over openwrt; it also affected component that handles booting and I ended up with a router that does a bootloop. It would try to power on (power led on) then all led lights will blink; then it will repeat again to the power led on. If you press the WPS/Reset button; the last led light (WPS) will light up for a few seconds then it will go back to the original bootloop pattern.
So I spent the next few hours trying to research on what would be the solution to solve this problem. One solution that was prevalent on the net requires opening up your router and connecting to it via serial cable. I don’t have the skills nor the equipment to do that so I thought I’m doomed to buy a new router.
But gladly, as I read through the comments on different blog posts showing how to recover via serial cable; I read about an alternative solution. This solution doesn’t require a serial connection.
This was the solution I followed in order to revive the router. Sharing the guide from this post where I add my own comments.
(Lifted and Modified from) Here is what you need:
1) A LAN cable
2) A machine running Windows XP or Windows 7 – I used Windows 10
3) The modified firmware (https://www.box.com/s/kps8yu3wszywuhqzy0c3)
4) A TFTPD Server, for Windows users I recommend (tftpd32.jounin.net)
Now follow this steps:
1) Set you PC lan adapter to fixed IP 192.168.0.66
2) Plug the lan cable in the PC and in the WAN slot of your router. I plugged it on the first Lan port
3) Rename the downloaded firmware from: MR3420v2_FactFirmware_NoBoot.bin to mr3420v2_tp_recovery.bin (all lower case).
4) Copy the file in the root directory of TFTPD
5) While holding the reset button on your router power it on and VERY quickly start the TFTPD server. or, have TFTPD server running before you power on your router.
If all goes well you should see information on the TFTPD server that the recovery file is being downloaded, after a short period you will notice the Led flashing differently on your router… job done.
Once I saw an activity in TFTPD; I was very excited and soon enough, the router had a different blinking pattern to it. I quickly checked 192.168.0.1 (router’s default address) and I managed to get it! My router is alive!
Hope this helps!
Till next time,