I have a modmypi wifi dongle connected via USB cable.
Just before takeoff I got two “communication” lost messages. I ignored this as I thought it was my Mikrotik routerboard taking over communications. Took off without incident and the craft hovered for about 30 seconds when it did an un-commanded roll and luckily crashed upright in to some grass.
I noticed that the Navio LED remained solid green and that the motors would not respond and was pulsing almost. I had to stop one of the turning props to disabled the battery.
Went home and noticed that when ever I thouched or wiggled the USB dongle that I would get a communication lost message and the whole system would freeze up.
So just a friendly warning that faulty dongles might cause crashes