The instructions for the deep reset are:
1. Power off the unit at the wall and give it 30 seconds for its power supply to fully discharge.
2. Press the reset pin into the reset hole (next to the LED status indicator) until you feel a slight click, and hold it in.
3. With the reset pin held in, power the unit back on at the wall, and keep the pin held in for 15 seconds, or until you see the status LED turn blue & alternate segments on the volume dial light up - then release the pin immediately.
4. Switch unit off at the wall again, and wait for all lights to go dark (this will take longer than usual).
5. Power the unit back on approx 10 seconds after all lights have gone out. The unit's LED segments should all come on around the dial, then go out one by one - this is the reset itself. Once all the segments have gone dark again, the unit should re-enter it's normal state of looking for the network briefly, then connecting.
Note - this reset does not reset the network settings, presets or any preferences stored on the Mu-so/Qb.