Reason 2: GPS hangs. This happens to me about a couple of times a month or so, when i start any app that uses GPS. The GPS status indicator is blinking, app does not get GPS info, and the indicator remains blinking after that until i reboot. Toggling flight mode does not help. The Settings -> Device -> GPS and Positioning menu content also does not respond in this case. Does anyone know of some other trick or command-line command to recover from hanging GPS without reboot?