Had some start up difficulties. But updated the YUN and IDE to the latest version.
* "/arduino/digital/13/1" works as supposed (turns on the LED) - it's just a bit slow. But I can't see why the analogs shouldn't work. I tried to connect it to 5V or GND, so it wasn't floating. But it still returns no reading.
Don't know if this is the cause. But when I connect to my router I can't the the YUN in the list of DHCP Clients...