I saw on another post that someone has a wifi box working with their own router by going into the diagnostics.
To get in the screen turn the mini off by the button on top. As soon as you turn it off hit the OK button on the remote. It might take a few times. Once in a white screen will come up. Hit the back button and go to option 4 which is Network Configuration. In there you can supposedly manually connect it to a different wifi network.