1. Prepare a microSD card.
2. Download and extract the software upgrade package / Stock Firmware
3. Create a directory at the root of the SD card wit name dload folder.
4. Copy update.app file to SD card at dload folder.
5. On the Home screen, click [Settings]> [phone upgrade]> [System Software Update].
6. Click the [local] Upgrade > [OK] > [upgrade].
7. Click the [Backup data], back up data to microSD card. If you do not back up your data, ignore this step, click on [OK].
8. Click [upgrade]. The phone will restart, and then enter the upgrade interface, start the upgrade software. The upgrade process takes about 3 minutes. The upgrade process, do not remove the battery, do not remove the microSD card. We recommend that you do not do anything, just wait.