i bought a Canadian factory unlocked white iphone 4 which came with 4.3.3 installed on it already... my phone is jailbroken. GPS on my iphone 4 is not working with any navigation apps (such as TOMTOM or Navigon). keeps telling me poor gps or there is no GPS signal avaible . GPS works fine with Google maps. i have tried restoring my iPhone few times (jailbroken it different ways as well), installing just one app on the phone to see if it works still poor GPS signals. is there any way i can fix this problem. please help !