I've got my Arduino Yun (less than a year old) connected to my computer via a USB cable. The device seems to be on (that is, the lights are all on). However, the Arduino is not showing up in either the /dev/ttyACMx (linux) or COMx on my Windows boot. Does anyone have any suggestions for why this could be? I've tried to reset the Yun to factory settings by holding the WRT RST button for 30+ seconds, but that still didn't fix anything.
I'm afraid that I'm now looking at a bricked Yun; if this is the case, what could / should I do?
Is there a chance that you loaded a sketch onto it using the wrong board type? For example, if you loaded a sketch while an Uno was selected in the IDE, the loaded code would not include the required USB port support.
Or, perhaps the bootloader got corrupted?
The solution in either case is the same: try to load a sketch over the network. This doesn't use the USB port, and it will load a fresh copy of the bootloader.
If the Yun's network port shows up in the IDE, select it and the Yun board type,then upload the sketch. You will need to enter your Yun's password.
If the Yun's network port does not appear in the IDE, build and verify a sketch for the Yun, and find the .hex file that was created. Now, log into the Yun's web pages, and at the bottom of the page there is a button to upload a sketch. Click it, navigate to your .hex file, and upload it. If your Yun's web interface does not have the upload sketch button, you may have to upgrade to a more recent version.