Note: You can upgrade your phone by Local Update method without unlocking your phone. The method suits for the situations listed below for sure: Update to Global Stable ROM from Global Stable ROM, Update to Global Beta ROM from Global Beta ROM, Update to Global Beta ROM from Global Stable ROM and vice versa. If you encounter the issue that the reboot page keep loading for a long time after flashing, you can choose to wipe all data via entering Recovery Mode. You can turn off your device and then hold both Volume+ button and Power button at the same time to enter Recovery Mode.