You will need:. SP_Flash_Tool_v5.1352.01, set VCOM drivers, firmware ipsw (links below)
Unpack the archive with the firmware (the directory to the folder with the unpacked firmware files must not contain Cyrillic characters).
Turn off your smartphone. The cable is not connected to the computer.
Extract the SP Flash Tool
Start the SP Flash Tool.zhmёm program ca.

Click on the Scatter-loading button in the image strelka1. MT6592_Android_scatter.txt and select a file (it is in a folder with the firmware) in the path to the folder with firmware MUST NOT be Russian and / or Chinese characters.

in the upper left corner of the Hit Options -on picture Arrow 3 in the opened window Hit Download, we check whether daw standing in the window DA DL All wit Checksum should stand.

in the window, select Download Only -on picture arrow 2.
Click the Download button.

Connect the phone to your computer turned off cable. The program should see it and start flashing. If your phone is not detected, it does not disconnect the phone from the computer at the same time it is necessary to hold down the Volume + button and the power button once popolzёt red stripe, release the buttons.
After the firmware disconnect the phone from the computer and turn on the device.