Downgrade P10+ from to 8.0.0.377(C185) to Nougat

[rumyaman]

I have downgraded my P10 plus from Emui 9.1 to Oreo (8.0.0.377 (C185) using Hisuite.
How can I further downgrade to the original Nougat. I feel my battery was working fine with the original firmware.

Could anyone give me an idea how it could be done.

Thanks in advance.

Rumy