OpenWrt Forum Archive

Topic: Cannot unbrick WNDR3700v4 with TFTP, Safe Mode, Sysupgrade; pls help

The content of this topic has been archived on 30 Apr 2018. There are no obvious gaps in this topic, but there may still be some posts missing at the end.

Apparently I bricked my WNDR3700v4 with a broken feature-rich image.

Cannot connect with TFTP, and nmap finds no host in 192.168/16 and 10.0/15. Cannot see an Ethernet address in arp either, but that might be me.
Cannot enter failsafe mode because the power LED turns from amber to off instead of green (tried anyway). This is probably when the image crashes.
Obviously cannot sysupgrade from command line or luci either.
Do I have to get a serial cable? Anything I can still try without opening the case?

Backstory: The official BB image for a WNDR3700v4 only provides 14MB of 128MB flash. I tried to work around this by flashing a CC image followed by a sysupgrade to BB without keeping the configuration. Seems I picked a broken image. Developers, please REMOVE BROKEN IMAGES from the servers before they do further harm.

It hardly helps you, but if it were a broken image, there would be plenty of messages on the forum or on IRC about images breaking routers. I think you just had bad luck.

Hope you get it fixed. You might need to use the JTAG interface to get it back to life.

Indeed it doesn't help, but after bricking my router I found posts to the effect that the build was indeed broken. It was found by another developer who had his device bricked. Do you want me to dig out that post?

Can you provide a link to the image you think is broken? "Feature rich image" implies it is not one released by the OpenWrt team, so they have no ability to take it down.

I'm only 99% positive which image I flashed in the end, and I don't want to make false accusations. It was 100% not one of the official BB release images.

Meanwhile I found the router at 192.168.1.1 with nmap -PR (ARP ping scan). After that scan I was suddenly able to tftp-put a BB image into it, though the regular ping gave no replies before and after the nmap scan.

Now I have telnet access (and still see only 14 MB flash). Thank you for your offer to help.

192.168.1.1 is always the default for OpenWrt.

Indeed 192.168.1.1 is the default, but getting no ping replies confused me. Still don't know why; there were no firewall rules on that interface... Not sure whether 192.168.1.1 is also the default in all builds of the feature-rich variants.

Maybe the WNDR3700v4 takes a little longer than others until it's ready for TFTP, maybe the ARP scan fixed something (like filling the ARP cache). I may never find out.

Anyway, by now the router is running a CC image, and I see 128 MB flash. Next step - falling back to BB.

Thanks again.

You might just kill it again if the flash layout varies between CC and BB. CC is pretty stable and a release candidate is expected soonish, so why not stick with it?

Hello Calmer!!
I have install your Version 15.05.1 what is the root Password to Login?
Thanks

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