[TheGreenCat]

Hi, i just flashed my "TP-LINK Archer C9 (V1)", and now the router just keeps turning ON/OFF over and over again. I searched the internet for solutions and it seemed like i have this BootLoop problem ore something.

This is what i did:

1) I downloaded DD-WRT version "06-16-2018-r36154".
With the 2 files "Factory.bin & Web flash.bin".

2) Loged in the router web UI

3) Upgraded the firmware with the "Factory to ddwrt" file. I used "FireFox 60.0.2" for this.

4) Let the upgrade take its time, and let it reboot.

Now this is where the problem started, it starts up, and i only see the lights "Wifi 5Ghz, wps, usb1, usb2" turn on and off again, and it keeps doing that non stop.

Now this is what i did next:

1) Downloaded the official TPlink firmware, and renamed it to "archerc9v1_tp_recovery.bin".

2) Downloaded TFTP, changed my ip to "192.168.0.66",
and connected a cable directly to my PC and Router.

3) Opened the TFTP software.

4) booted up my router while holding the reset button, the file transferred successfully.

And after that, it starts all over again.
The same lights keep doing the same stuff.
Now my question is, what do i do now?

[louierh70]

Hi,

I experienced exactly the same thing with my Archer C9 V1 after I flashed it with DD WRT the first time. I tried the TFTP method to ubrick it but it didn't help. So finally, I decided to just open the router and used a USB to TTL adapter to flash the router. You can find the steps from here:

https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=283784&postdays=0&postorder=asc&start=90

Check the 4th post from reroute and download the pdf where the steps are explained. You can also check on Youtube:

https://www.youtube.com/watch?v=fme7kwTkttk&t=982s

After unbricking your router and you still want to use DD WRT, download firmware r27506 and use this to install DD WRT. Anything newer than this firmware will not work (at least in my case). After you have successfully installed r27506, you can easily upgrade to a newer firmware using the DD WRT webgui. Im currently on r35531 and it's very stable on my router.

[TheGreenCat]

Thank you louierh70.
Was afraid i had to use something like this.
However, is their no other way to fix it without opening up my router, and connect this USB adapter in it?
I dont have this USB device thing, and dont have experience with this kind of stuff.

So if i understand this correctly, the only thing that is broken is the "boot file", nothing els?
And thats the reason why it doesn't want to install a new firmware in recovery mode then?
Its silly that TP-LINK dint build in some sort of fail safe, that just wipes out the Flash/memory chip first,
and then install the firmware in recovery mode. That would make sense.

[louierh70]

Unfortunately, I don't think there is another way aside from opening the router. Your case sounds exactly like mine, whereby I installed the newest dd wrt version directly after getting my Archer C9 V1 and it went into a boot loop. I spent 3 days trying all the methods to unbrick the router without opening it but nothing worked. So finally, I just decided to open it. You can buy a cheap USB to TTL converter like this:

https://www.amazon.de/gp/product/B0757FQ5CX/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

and some connector pins which cost a few cents. I have no soldering experience whatsoever so what I did was, I brought the motherboard of my router to a cellphone repair shop and asked them to solder the pins for me. I paid a few euros for this service. After that, I just followed the instructions in the pdf and in Youtube. I think, if you were capable of making the TFTP method work, you should have no problems repairing your router. The most difficult part, at least for me, was soldering the connector pins on my router and like I said, I had somebody else do that for me. Once the pins were soldered, the rest was quite easy.

Also, I left the connector pins on the motherboard in that way, in case I encounter problems in the future, I can easily fix it. Then you can play around and try different dd wrt builds without worrying. In fact, the first time after I unbricked the router, I tried installing one of the newer builds of dd wrt and again I encountered the same problem so finally I just installed the old version I wrote in my previous message and after it worked, I upgraded to a newer one.

[MolaMola]

Build 35244 is running fine on my v1 here. No boot loops. I think others reported similar success. Later builds indeed seem to have problems.

[TheGreenCat]

Once again, thank you louierh70.
Nice that you gave me the right product on Amazon.de, i sometimes order on that website too.
I will order one, and try it out with going to a specialist to solder the pins for me.

Thank you.