Opened 3 years ago

Last modified 2 years ago

#18318 new defect

NEXX WT3020 LED & Reset button issues

Reported by: bradley.will@… Owned by: developers
Priority: normal Milestone:
Component: packages Version: Trunk
Keywords: Cc:


Using this image last updated 23-Oct-2013: uploaded to my new NEXX WT3020A.

I changed the main LED setting a few times to settings like WiFi, TX, RX, etc. When I changed it to "pwmtimer" the setting applied but the Web GUI froze and the router began power cycling. The LED lights up at full brightness, then dims to about half-brightness once booted (Wireshark detects a few MDNS-type probe packets) and then freezes. 30-50 sec later, it reboots (LED goes off and comes back on.) No DHCP, ping, or other response even when setting the ARP entry by hand.

Attempts to boot into failsafe mode have also failed despite asking on IRC; repeatedly pressing the reset button before/after/during the Failsafe UDP notification seem to only have the effect of stopping the boot process. Again I can't reach the device on the LAN port even when I manually set my IP and add the router's MAC to my ARP table. Waiting 5 minutes proves it is definitely frozen, only power cycling will do anything.

I'd suggest removing the PWM LED feature until further testing can be done on the NEXX WT3020A. It shouldn't be possible to brick a router by playing with fun LED settings. Also, it might be good to double-check that failsafe mode works as documented on the WT3020A.

I've ordered a TTL adapter, will update this ticket if I learn more. Cheers!

Attachments (0)

Change History (7)

comment:2 Changed 3 years ago by anonymous

I can also replicate that issue. It is important given the fact the failsafe of openwrt is broken for this board. Luckily I had updated the bootloader to one with inherit failsafe.

comment:3 Changed 2 years ago by Litonx

I juste made the "error" of trying the "pwmtimer" in LED settings. I have the same trouble as you. I have the stock bootloader (haven't done anything else than flashing openwrt). Does that mean my WT3020 is broken or I can flash the firmware or a bootload with working failsafe mode over TTL serial ?

comment:4 Changed 2 years ago by bradley.will@…

I was never able to get it to respond to TTL serial afterwards, though I don't know if it ever worked to begin with. It's as though it didn't accept any keyboard inputs, I'd see the boot messages scroll by but I couldn't get it to stop boot and enter failsafe. Maybe you'll have more luck than me.

Maybe related to Anonymous's comment#2 above.

comment:5 Changed 2 years ago by Jonas

I encountered the same bug, it can be tested safely on the command line.

   cd /sys/devices/gpio-leds/leds/nexx:blue:power
   grep pwmtimer trigger
   echo pwmtimer >trigger

If grep returns results pwmtimer is available. With the bug the echo line will cause immediate lockup, you will not even get a new prompt. After a little while the system will reboot and work normally again.

I tried removing the patch pointed to by bradley.will and this fixes the problem by removing the broken pwmtimer.

comment:6 Changed 2 years ago by bradley.will@…

Thanks for the update Jonas, do you know of any way to recover a device after enabling the PWM LED in its config? My little NEXX has been bricked for a year, since I haven't been able to get into failsafe mode ;)

comment:7 Changed 2 years ago by Jonas

Unfortunately no, at least not an easy one.

I haven't had the need for the failsafe mode myself, but I understand that it's broken on the WT3020. There is a third party uboot for which there is no released source code that can be used for rescue, but you need to install that before bricking.

I can think of two possible ways:

1) If dropbear is started before the LED is set you might be able to script something that logs in and changes the setting before it locks up.

2) Bring out the soldering iron and write to the flash ROM with SPI. You might be able to get some help doing that here:

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