We recently talked about how the Xiaomi Mi Mix 2 received official support for TWRP and now the device has just received its first official build of LineageOS 15.1. XDA Recognized Developer mikeioannina brought this to our attention here in our own forum for the Mi Mix 2 and we’re already seeing a lot of people using the build. mikejoannina recommends those who want to install LineageOS 15.1 after coming from another custom ROM will want to factory reset the device first.
However, some have reported getting a “Google services framework has stopped” error when switching from another custom ROM. This seems to be from a conflict with the encryption method, so you may need to do an advanced wipe, install the ROM, reboot into recovery, and then do another advanced wipe before you can install the ROM and the recommended Gapps package. You can download this first build directly on the LineageOS website here and then choose your preferred variant of OpenGapps from here.
Check out this build of LineageOS 15.1 in our Mi Mix 2 forum