thry this I read on forum nokia
in Garmin go to TOOLS, SETTINGS, MAP, ORIENTATION, and change this to TRACK UP, ONLY BELOW 300ft. Then when you go to navigate have the map overzoom set to 200ft.

Also, it seems to help if one turns off the cellphone, restarts the cellphone and only run Garmin XT (and don't run any other applications at the same time), so as to have as much RAM allocated for the Garmin application.