As with some other Lenovo devices, this Lenovo A6020a40 flash file can easily be flashed via SP Flashtool.
Download from below and follow instructions at post end to learn how to flash, and or download SP Flashtool.
DOWNLOADS
Vibe K5 note A7020a48 – Download
Also see: Lenovo Vibe K5 A6020l36 official firmware
FLASHING INSTRUCTIONS
Click here to download SP Flashtool and learn how to use the tool.