Hi, iphone users, My iPhone is a 3GS 32GB model. After I upgraded the phone to the official os 4.3.3, the GPS became inaccurate like always one block away from the true position. Is this an unique issue or common problem? My baseband is also updated (05.16.02). My phone is still in warranty. But I keep my phone very well and it stills looks perfect. I wonder how good is the condition of the replaced phones from apple? Is it better to do replacement in their retail store? Thank you very much for your help.