When i am in radio function, i can use the MODE button on the side to switch in a different screen (multiple icons appear in that new screen) and then i can choose Navi, CD, SD etc...
when i am in Navi function, that MODE button works in the background but the Navi screen remains, the only way i found to exit the Navi screen is by turning the unit off.
There was no instruction manual with the unit and all though the seller is very cooperative, he hasn't given me a solution yet so i'm leaning toward this being a Hardware related problem.
Really not cool....i like fixing things and this one is driving me crazy.