I've heard that there's been some problems with the Mi Box S software. Were they stable with Android 8.1? If so, can you stop the update push? I want to put a few boxes in my spare bedrooms with Tivimate and have Netflix, Prime Video available for guests. Otherwise no plans for Kodi or anything heavy.
You won't get Prime video without upgrading to pie tho.
I did the upgrade and i have no issue. people recommend to do a factory reset after installing the update but i couldn't be bothered setting everything back up, so i just left it. 0 issues.