I have a USB 2.0 802.11N wireless adapter from ThePiHut and I am using it in a 2011 Raspberry Pi which is connected to my router via Ethernet. When I go into the OpenELEC settings then into networks it displays my router with the state ready. there is also an IP address and the interface is wlan0. Wireless networking has also been enabled. So why when I disconnect the Ethernet am I no longer able to control the Raspberry Pi with my mobile phone? something I am able to do with Ethernet connected.
The problem was that OpenELEC set a open wifi network as the default connection, and not my home network, so it kept connecting to the open network. I simply set my home network as the default connection and I was able to use my phone to control the Raspberry Pi again. Now it always connects to my home network.
The lesson here is to make sure the network you normally connect to is set as the default connection and every time OpenElec starts up it will connect to it. Providing the connection is available.