Lenovo A6020a40 VOLTE Firmware..
First flash this version with qfil..
https://docs.google.com/uc?id=0B1hm-6TNn10IcUtHOWZLaUtzUEU&export=download
Then Flash this OTA from recovery..
https://drive.google.com/file/d/16IFErGeGzxC3eE5kwWB4oWm50Dn_shUz/view?usp=sharing
After that check for OTA update from setting.
