Just before setting off for work this morning, I noticed that the Nav screen was showing quite a zoomed out view, so I pressed the zoom-in button and then thought nothing more of it as I started driving. A while later when I glanced at the Nav screen, I noticed that the map was still showing my home location. I tried pressing the buttons around the Nav screen but it didn't respond to any of them. The audio was playing OK from USB and I could turn the audio on/off by pressing the volume knob, but that was all I could do to the unit. When I arrived at work I turned the ignition off and then on again. The Nav unit re-initialised and now responded to the controls again. I will have to wait and see if it is working normally on the way home later today. Is this a known problem with Honda HDD nav units?