On this page, you will find the official link to download Lenovo Vibe X3 X3a40 Stock Firmware ROM (flash file) on your Computer. Firmware comes in a zip package, which contains Flash File, Flash Tool, Driver and How-to Manual.
Download Lenovo Vibe X3 X3a40 Stock Firmware (flash file)
File Name: Lenovo_X3a40_USR_S122_1511021007.zip
File Size: 2 GB
How to Flash: Follow Tutorial