Itel it6900 official firmware requires Research Download Tool to flash. All required tool and relevant drivers are available in this post.
Download the firmware from the link below and follow flashing instructions after the download options.
File Name: iTEL IT6900-G400-ArEnFr-EG-20160125_RELEASE.rar
Size: 7.26 MB
Firmware Link – Download
HOW TO FLASH
Click here to download Research Download and Upgrade Tool, and learn how to use.
If after flashing and the phone’s language is not in English, just navigate to Settings menu, find Input/Language and change to English (or your choice language).