It is possible to downgrade upgraded iPad’s baseband on iPhones. The upgrade is provided to make it possible to unlock iPhone on any carrier. You mistakenly might have upgraded your iPhone to official firmware without knowing that it will also upgrade your baseband that is not supported by ultrasn0w to unlock. Then you don’t have any choice left but of upgrading your iPhone’s baseband to 6.15.00 or using it as iPod till any solution released. But upgrading to iPad’s baseband can stuck your GPS efficiency.
But soon it is going to be possible to downgrade your upgraded baseband 6.15 to lower and unlockable. On September 17, 2011, MuscleNerd from iphone DEV TEAM had confirmed in response to a Twitter user’s question that soon they will release something to downgrade the upgraded iPad baseband 6.15 to 5.XX that can be unlockable using ultrasn0w.
Many people have upgraded their iPhone baseband to 6.15 to unlock the device to work with any carrier, but this upgrade have caused the GPS issue. Everyone who have upgraded their device baseband to 6.15 are experiencing the GPS issue and expecting a fix to downgrade this. It’s been almost 4 months and the fix is about to release very soon.
Till then keep fingers crossed!
You can fix your GPS issue by following a small trick.