BlackBerry® Device Software 4.0 Service Pack 2 (4.0.2) and 4.1
The BlackBerry 7100i and BlackBerry 7520™ have built-in Global Positioning System (GPS) functionality that can be accessed via Research In Motion® application programming interfaces (APIs). Applications that use these APIs attempt to use autonomous GPS fixes as the primary source of most accurate GPS data.
If you use BlackBerry Device Software 4.1 for the BlackBerry 7100i or BlackBerry Device Software 4.0 Service Pack 2 Bundle 54 for the BlackBerry 7520™ and acquire a cellsite fix, it is impossible to acquire further autonomous fixes unless you perform a hard reset of the device.
Complete one of the following:
To avoid code change, use BlackBerry Device Software 4.0 with the BlackBerry 7520™ (there is no such option for the BlackBerry 7100i).
If you do not change the device software, a code change could be made to the application to avoid using cellsite fixes. As an alternate method of acquiring GPS data in the absence of autonomous fixes, you can acquire assisted GPS fixes where available.
For more information on the types of GPS fixes available, see this artcle.
You will be able to acquire cellsite GPS fixes with BlackBerry Device Software 4.1 maintenance release.