1.-Take the battery out of your phone
2.- run the "SP Flash Tool" as "admin"
3.- Press the "choose" button in the "Scatter Loading File"
4.- Select the file "MT6572_Android_Scatter.txt"
5.- Select the appropriate option "Download" or "Format All + Download"
NOTE: Using "Format All + Download" only if necessary, you risk not turning the phone on if Finrware is not downloaded to the device
6.- Press the "Download" button without connecting your device
7.- Connect your USB cable to the computer, now connect your device and insert the battery at the same time
8.- Wait for the installation to complete, do not move or touch the phone in the installation process
9.- once the process is finished, disconnect the device, remove the battery and put it back, turn the phone on
10.- On the first start it will take 3 to 5 minutes to turn on, if on power up only shows the "ZTE" logo soon after 10 minutes, remove the battery and turn on "Hard Reset" mode, select "Wipe Cache" and " Wipe Users Data, then "Reboot System Now", will turn on normally and initiate corresponding settings.
NOTE: If the installation fails, check the cable used, check the charging port of the phone, the phone card may no longer support writting for damage to the EMMC