On this page, you will find the official link to download Lenovo S820 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 S820 Stock Firmware (flash file)
File Name: Lenovo_S820_AMX_MT6589_B123_14010.zip
File Size: 951 MB
How to Flash: Follow Tutorial