Xiaomi Mi Mix 2 useer looking for help



I’m hoping to find an answer to my question regarding rooting my device as well as flashing a new custom ROM.

I am currently running Lineage OS 15.1 on my Mi Mix 2. I’ve been waiting for Android Pie for some time now and I have finally found an Official ROM compatible with my device.
I would like to flash Potato Open Sauce Project ROM.

My question is, if I first have to flash the latest MIUI 10 ROM to my device in order for it to work. Or is this no longer necessary because I am already on a custom ROM (LOS 15.1)?

I’m looking forward to finally getting Android Pie on my phone! :slight_smile:

Thank you!