I have an iPhone 4 on iOS 5.1.1 which was jailbroken long back. We have not installed any new tweak or even app store app for last 2 months on this phone. But suddenly there is an issue with this phone. The sound from speaker is completely mute when the phone is in jailbroken mode. Ringer and even music sounds. Tried to manually increase sound using hardware keys and also sliders within the sound settings but no go. I cannot even see the sound slider within the music app and not in App switcher as well. But if I connect the earphones sound starts working fine. How can this happen suddenly ? What possible troubleshoot ?