R8000 Bricked NO CFE

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soccermadman
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Joined: 19 Mar 2010
Posts: 20

PostPosted: Wed Oct 02, 2019 2:04    Post subject: R8000 Bricked NO CFE Reply with quote
Hi All -

I have two different TTL 3v3 cables, one with a prolific chipset and one with a FTDI chipset. I can't get output other than this from my R8000. The router has NEVER been overclocked, and was bricked applying the latest Kong build (I haven't touched this as it sits at my in-laws house, since sometime in 2017). I can't get the ethernet ports to even show link up with a device, let alone ping the router.

Example of the only thing I seem to be able to get the device to do:
https://imgur.com/LOLSI2t

I have tried both cables, with GND,TX,RX (and flipped TX/RX til I'm blue in the face) and I also tried to let the device boot for a second before connecting ground as others have reported that can interrupt boot with some cables. I used the diagram from here: https://www.myopenrouter.com/imagelib/contentitem/56764/11d1def534ea1be0--7cabdc19-147fe628ea2--4680220333684.jpg

for the pinouts.

I have tried to use multiple different COM port speeds, starting from 9600 and working up to 115200. I have tried booting the device while holding reset, and that didn't help either.

Is it possible that CFE is damaged on this device in some way?
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kernel-panic69
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Joined: 08 May 2018
Posts: 2343
Location: Texas, USA

PostPosted: Wed Oct 02, 2019 4:32    Post subject: Reply with quote
The serial recovery wiki will tell you how to configure PuTTY. That there is either no ground or the tx/rx leads are reversed, I am thinking possibly no ground, but it could be the pinouts are wrong. Have you verified pinout with a multimeter? I just went through the fun of bad information recently while trying to connect serial to an R7000P is why I asked. Once you verify ground pin and +3.3V, the rest is easy to figure out.
Malachi
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Joined: 17 Jul 2012
Posts: 7231
Location: Columbus, Ohio

PostPosted: Wed Oct 02, 2019 9:16    Post subject: Reply with quote
Where are you located? If you are willing to pay for two way shipping, I could try.
I have recovered a few routers for forum members before.

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soccermadman
DD-WRT Novice


Joined: 19 Mar 2010
Posts: 20

PostPosted: Thu Oct 03, 2019 2:10    Post subject: Reply with quote
kernel-panic69 wrote:
The serial recovery wiki will tell you how to configure PuTTY. That there is either no ground or the tx/rx leads are reversed, I am thinking possibly no ground, but it could be the pinouts are wrong. Have you verified pinout with a multimeter? I just went through the fun of bad information recently while trying to connect serial to an R7000P is why I asked. Once you verify ground pin and +3.3V, the rest is easy to figure out.


I know that pin 1 is 3.3v, I know that pin two seems to be a ground. Is it possible the ground pin is just bad? Should I try grounding to something else? I have tried all combinations of the non 3.3v pin as ground,tx,rx. This router previously had OpenWRT, several different DDWRT builds, LEDE, and tomato on it. I have recovered from a brick before, I just literally can't get anything out of it this time to even start the process.
Brimmy
DD-WRT User


Joined: 29 Mar 2015
Posts: 381

PostPosted: Thu Oct 03, 2019 3:24    Post subject: Re: R8000 Bricked NO CFE Reply with quote
soccermadman wrote:
Hi All -

Example of the only thing I seem to be able to get the device to do:
https://imgur.com/LOLSI2t


I am currently in the same situation as you but on a Buffalo WZR-1750DHPD. I can't reset my router as the build that bricked one of my routers was a build that had the reset left out/messed up in the build.

If you reverse the TX and RX connectors, leave out the ground and use Putty you will/should get a CFE read out when yo turn on the router but you may not be able to do the crtl + C to get the break for the command window to open.
foz111
DD-WRT User


Joined: 01 Oct 2017
Posts: 208
Location: Earth

PostPosted: Thu Oct 03, 2019 12:48    Post subject: Reply with quote
using multimeter & using metal shield for ground find power pin, once you have power find ground pin using multimeter, then normally rx and tx are the other 2 as you correctly stated simply swap around if you get garbled code back in putty window.
what you have not mentioned, was the router functioning correctly prior to bad flash or were you flashing it due to issue?
it could be hardware failure?
soccermadman
DD-WRT Novice


Joined: 19 Mar 2010
Posts: 20

PostPosted: Fri Oct 04, 2019 0:10    Post subject: Reply with quote
foz111 wrote:
using multimeter & using metal shield for ground find power pin, once you have power find ground pin using multimeter, then normally rx and tx are the other 2 as you correctly stated simply swap around if you get garbled code back in putty window.
what you have not mentioned, was the router functioning correctly prior to bad flash or were you flashing it due to issue?
it could be hardware failure?


Hi - it was working before I flashed the latest Kong build. The version on it before I did that was from early 2017, and I wasn't sure if it was vulnerable to any of the crap that these routers are affected by so I figured I'd update it. I have performed this serial recovery before on this device and the pins I used matched what was in the document I linked.i didn't have my own ttl then, I borrowed someone else's. However I have two now and neither is working. I may try a little more tonight but I think this thing is dead.
Malachi
DD-WRT Guru


Joined: 17 Jul 2012
Posts: 7231
Location: Columbus, Ohio

PostPosted: Fri Oct 04, 2019 1:09    Post subject: Reply with quote
Could be your adapters are bad. If you connect your tx and tx together, are your keystrokes echoed on the screen?

You didn’t answer me on my previous question but if you are going to throw it away, I’ll take it.

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soccermadman
DD-WRT Novice


Joined: 19 Mar 2010
Posts: 20

PostPosted: Sat Oct 05, 2019 5:01    Post subject: Reply with quote
The device was able to boot randomly. I don't understand, every once in a while it will start up finish the light test and start to boot. I still get NO CFE output. I'm going to try to replace the CFE with one I found on the forums here that I edited. I _REALLY_ don't understand. I just tried CFE with two other adapters that a friend has I now have two random Chinese ones off ebay he had (one with wires and one that's all in one on a PCB) plus both of mine. None of them get any output in any pinout configuration.

Edit: and by randomly boot, I mean it boots about 1/35 or 1/40 power cycles. I've got it to boot twice total
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