USB led always ON

After working properly for a few days my Yun has lost its Wifi connection and stopped working.

Before performing a reset I would like to know if there is something I can do to explore the reason.

The only strange symptom I can see is the fact that the blue USB light is now always ON (and wasn't when everything was working fine).

The Led turns and remains ON after a few seconds after Powering On the board regardless of where the power comes from (Vin or USB).

Any hints?

Load the serial terminal sketch through USB open the serial monitor. Push send see what you get. If nothing push the reset by the LEDs you'll see the linino boot process.

Thanks pal, before "acting" on the board (reset and/or loading a new sketch) I'm trying to see if there is any way to find out what may have caused the error.

See if you can ssh in through the Ethernet port. The yunserialterminal sketch is the most unobstrusive way I know other than that if the WiFi is dead.

What os are you running on your host box? In Ubuntu I open a terminal and either ssh root@192.168.x.x or ssh root@.local.

simon, just in case: can you take a screenshot of the yun when it's powered?

Noblepepper, many thanks for your hints. I’m running Windows on my computer.
Since the Yun’s wifi is dead in order to load the yunserialterminal sketch it means I’ll have to reset the board…

Federico, I’m a bit confused by what you mean by a “screenshot”, since the Yun is not communicating with the PC I have no screenshot to capture

Sorry guys if I’m being to naive, maybe I’m missing something.

Will wait for your last feedback before moving forward with the reset.

Many thanks for your support

Federico, I'm a bit confused by what you mean by a "screenshot", since the Yun is not communicating with the PC I have no screenshot to capture

My fault, sorry, I'm too used to ask for screenshots of the IDE for understanding how it misbehaves, that I confuse pictures with screenshots.
I meant a plain old picture: please, take a pitcure of the yun with that led turned on and attach it to the forum

Federico, here it goes…as you (hopefully) can see the USB led intensity is much weaker than the Power ON led but still ON.

Hope it helps.

If you connect your Yun's Ethernet port with a cable to your network router you may be able to ssh in to it that way. You'll need PuTTY to do that you can get it at Download PuTTY: latest release (0.76). I will be a lot easier to find your Yun on the network if you have Bonjour installed too. arduino.local doesn't work - #10 by noblepepper - Arduino Yún - Arduino Forum, other wise you'll need to look up it's IP in your router's DHCP clients table.

Start PuTTY and put your Yuns name or IP in the Host Name box, connection type should already be SSH. Click OPEN and you should get a login prompt, log in as root using the password you set on the Yun. You should get a splash screen.

I suspect your Linino side is down and you won't get any response.

See what Federico says before you reset anything.

Simon, please copy paste your first post to


Did you find a solution?