I discovered when I was messing around in the driveway, when stationary (or going slow) it changes to north up, I guess it is a default because the boat is not moving, it has nothing to reference direction to, so just goes north up, because the satellite updates are so slow on these "old" technology units, the device just toggles from head up to north up when going slow, and the map (and your position/direction) swaps back and forth too.