1.copy OTA_INT_010_all_150828.zip to root folder of the phone SD card (no need to unzip). 2.Turn off the phone, then keep pressing power button and volume+ button until the robot icon appear, then press power button again 3.Press the volume- to move up and down to choose“wipe data/factory reset”, then press volume+ button to confirm. 4.Choose “yes—delete all user data”, then press volume+ button to enter the page as below. 5.It will enter below page after finishing delete all user data. 6.Then choose“apply update from sdcard” 7.Find and select the ROM, press volume+ to enter the page as below. 8.Please make sure the power is sufficient during the upgrading. It will showed as below when the upgrading finished. 9.Choose “reboot system now”,then press volume+ button to reboot your phone.