OpenWrt Forum Archive

Topic: Command /sbin/reboot fails on TP-Link WDR3600 hw-version 1.5

The content of this topic has been archived on 30 Jan 2018.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

I have been running AA successfully on TP-Link WDR3600 hw-versions 1.1 to 1.4. However, on hw-version 1.5 the command /sbin/reboot sometimes fails -- the device goes down but does not come back up. Power cycling the box gets it up again, provided you have physical access to it.

I did some experiments using both hw-versions with AA and BB_rc2, logging in and running /sbin/reboot from the command line. The results:

HW-version 1.4: /sbin/reboot works every time (10 out of 10)
HW-version 1.5: /sbin/reboot fails 3-4 times out of 10 attempts, both on AA and on BB_rc2.

This is not just a bad apple, I have tried three different devices (hw-version 1.5) and the results are consistent. Any ideas?

After some googling I found another way to reboot the device: "echo b >/proc/sysrq-trigger" . Is it OK to use this command instead of /sbin/reboot? Or is it even preferrable?

Anyway, although it looked promising at first, this command also fails to bring the device back up again at times.

The story continues: I flashed six devices (hw-version 1.5) with AA. Then I made cron run a reboot-test (using echo b >/proc/sysrq-trigger) every 2-3 minutes.

(The cron-entry is "* * * * * /root/", but booting takes some time, too).

After a good hour hour of running half of my devices have ceased functioning, two of then within the first 10 minutes. The other three are still ticking.

There seems to be significant variation in the quality/stability of the TP-Link devices. As stated earlier, I never had any issues with previous hw-versions. In fact, I believe I have had several stable 1.5 devices as well.

How much "micro-versioning" can there be between two versions, e.g. between 1.4 and 1.5?

maybe a serial log of the hanging could show some hints about why it's not booting ok.

in the past sometimes micro-versions had slightly different hw (chips revision etc..)

Thanks for your prompt reply.

Unfortunately, I must confess I have no idea of how to produce a serial log. Any pointers?

An update on the reboot-test: after 24 hours of running two (2) out of six devices are still running. The other four are hanging.

I have the same problem with the reboot at a TL-WDR4300 V1.7 and OpenWRT BB-RC3.
Sometimes the router hangs after the reboot command and a power cycle is required to get it back to live.

I have a TL-WDR3600 v1.5 with BB RC3 with the same problem... The reboot via ssh or luci fails and it need a power cycle

Here is also an ongoing discussion about a reboot problem with a TL-WDR4300:
So far as I know has the TL-WDR3600 and the TL-WDR4300 nearly the same hardware inside (except of the WiFi part) and so we a probably talking about the same problem.

There came also the idea up, that maybe an additional installed software module causes these problems.
Did you guys install extra modules which are not included into the original OpenWRT firmware package at your router?

Which RAM does your board have?

We found:
Devices having reboot issues are eqipped with Zentel A3R12E40CBF
Devices without reboot issues use SKhynix H5PS5162GFR
Devices without reboot issues use Winbond W9751G6KB-25

Can you confirm?

I can confirm, reboot issues here with "Barrier Breaker"

(Last edited by ghiki on 3 Nov 2014, 03:16)

The discussion might have continued from here.