All,
I own a F900BT (upgraded to 3.01). In the spec it said it also uses a gyro sensor for when the GPS signal is lost. However on several occasions when driving through a tunnel, the Red Arrow (which I belive to be me 
) just continues straight ahead.
Has anyone figured out how to verify the internal sensor(s)? I found one post that on the F500 there is a 3D hardware menu for doing this, but I haven't come accross any menu like that on my unit.
thanks
Weo