In iGS618, the North-upward function is fixed ,and it can't roate automatically when navigating on a map.
But it will rotate automatically when navigating without any map.
Steps: connect the device with a computer to delete the map under the "navigation" folder
The North-upward function can be chosen to be fixed or not in the device iGS620.
Steps: Navigation>navi Setting>North-upward on.