Since I use my WiFi as my primary connection to the Yun I haven't run the sketch mentioned on the main Yun product page to disable it but I believe it mainly comments the wifi-live-or-reset in rc.local.
http://arduino.cc/en/Main/ArduinoBoardYun
If you wish to disable WiFi, run this sketch. For more information, refer to this forum post.
http://forum.arduino.cc/index.php?topic=189105.msg1399047#msg1399047
You may think it is very easy to disable WiFi interface using the OpenWRT bare control panel LuCi.
http://arduino.local/cgi-bin/luci/admin/network/wirelessHowever, you will be noticed that Yun will reboot every 60 seconds if the WiFi interface is disabled. This behavior is intended by the Yun developer. You have to bypass or "fool" the WiFi detection function in Yun. This requires a small modification to the Yun's Linux part.
Since the Wi-Fi connection seems do not work with liability (for
manysome people, and maybe it is causing other problems...)
Do you mean reliability? For a FEW people there are problems with wifi. I have no problems and have seen the Yun stay connected to my WiFi network for WEEKS. The only times I have seen it disconnect are when I have done it intentionally or my network has gone down.
What other problems do you think are related to YOUR wifi problems? Why do they seem to be caused by wifi issues?