- Last Active
You can completely erase - in that case - everything on the present card before updating. Anything an update has placed on a card can be deleted before a new update.
Updating, after all, can be done on a new - and therefore empty - card.
My "automatically generated" waypoints on my 20 were always the result of the joystick being pressed while in a pocket.
I bought a camera belt-pouch for it, and cut off part of the front (in a V-shape) - the part that is in front of the stick. The 20 lives facing out. There is now nothing to press the stick in normal use.