If during the jailbreak process on iOS 7.1.2 using PanGu you encountered this error “It seems that the device did not reboot, please reboot manually”, there is a very simple and quick solution for it. This error is displayed when PanGu do not recognize an Apple device that has been rebooted, or in some cases refuses to reboot. Actually, the fix is quite simple and it’s only one step!
You must enable Airplane Mode before starting the jailbreak procedure. Yes, that's it!
Activating Airplane Mode your device will start quicker and PanGu will recognize it without problems during the jailbreak procedure without displaying the error.
If you wish to jailbreak your device running iOS 7.1.2 just follow this tutorial using PanGu.