I've recently had a puzzling problem with my 998, which is just over a year old. The problem is 2-fold:
1. When I restart the unit, my recent tracks are often incomplete and displaced by several miles. Since I'm running between known way points, the displacement to areas of the chart with no way points is very apparent. When I export to Humminbird PC, the same displacement is seen when I view in Google Earth.
2. After I export all data to the SD card, I routinely go back and delete all navigation data using the usual command. However, when I reinstall my way points from the SD card after deleting the tracks in Humminbird PC, some of the older tracks still appear as dashed lines on the chart.
Any ideas about this problem? Is there someway to reformat the memory registers on the unit to be sure that all of the old data is removed?