I purchases a Yun and considering the disappointment so far it might be a flawed product.
First. Feeding 5V to Vin does not work at all, completely dead. Well, there goes my plan to use it in my robot project. It will have to be connected to USB power the rest of it's life. I maybe would have sent back the device at this time but I wanted to gain some experience with it. It was also discovered after some days filled with lots of other frustration, and a month after purchase. I am not sure about the return policy.
I manage to configure and connect it to my network. I connect it to the IDE and sometimes manage to download sketches. It occasionally works and sometimes not at all. I know the rule "Tell me what what the problem is or we can't help" but I am simply unable to describe a completely erratic behavior. I try to do according to some of the examples and tutorials but the basic rule is: "It never works the first time". A normal day with my Yun is start up the device, get the blue led and it to be visible in the network, start IDE on my computer and do something else for half an hour and then maybe, maybe it will show up with it's IP address. I could choose to connect with USB cable but I really think that connecting with wifi should work, it is so to say what it is built for and what I pay extra for.
Anyway, there is linux on the device I have been told. I am not very experienced but I know some things about how to write commands from a terminal window and the arduino home page writes a little about how to do. So I start terminal and write ssh root@myipadress. Nothing happens, connection times out. So give a few other tries without success. Then write ssh root@deivename.local more by chance and it connects showing a nice Open WRT logo (Later it worked to type the IP address, no surprise since the rule "It never works the first time" applies here also). I am told the the command "ls" shows files and folder. I type it and nothing. Empty. Should it be like that? I thought there was a file system and "things" like python and other stuff. Or am I supposed to create something of my own.
So I suspect that I need an update of Open WRT. I download to an SD card and try to do according to the tutorial, neither by the web panel (the reset button never shows up) or writing "run-sysupgrade /mnt/sda1/openwrt-ar71xx-generic-yun-squashfs-sysupgrade.bin" in the terminal. (Also here, after writing this I did another try and the file and reset button showed up in the web panel, the rule still applies)
So here I am, 50 € poorer and quite a lot more frustrated than before I bought the Yun. So go ahead and tell me I am too stupid for this device.