This morning when I fired up the GPS I had a black rectangle in the upper left portion of the screen.The rectangle took up perhjaps 20% of the screen. Since this mornings flight was a short reposition I continued without touching the GPS to see what would happen. I am in track up mode. The first couple of turns after take off the black rectangle repositioned itself as the map shifted to follow my track. After 5 minutes or so the screen completely filled in with map and all was normal. I didn't bother with any updates before the flight.
Just a glitch--- or something worse about to happen?
Paul
N1431A
2AZ1