Google Pixel 2 XL was released in 2017, October with Android 8.0 Oreo out of the box with trending features. Recently Google has released Android 8.1 Oreo with some new features added. With the release of new Android 8.1 Oreo, the parallel thing that happens is the development of the Custom ROM which essentially acts as a wrapper to the underlying Android version. After the huge hit of Lineage OS 14.1, Lineage OS team started building new Custom ROM LineageOS 15.1. LineageOS 15.1 is packed with all new features of Android 8.1 Oreo. As this is the initial stage of development the official builds are not yet released. This unofficial build may not work as a daily driver as you expect. As official builds are under development, you can wait until official release. But if you can to test this LineageOS 15.1 ROM on Google Pixel 2 XL and taste the latest Android 8.1 Oreo features. Follow the below step by step guide to install LineageOS 15.1 on Google Pixel 2 XL. The developer RaymanFX has compiled the unofficial LineageOS 15.1 builds for the Pixel 2 XL. Recognized Developer RaymanFX in XDA said DO NOT FLASH 3RD PARTY GAPPS PACKAGES!.

Pre-Requirements:

Make sure the bootloader on your device is unlocked and your device is rooted and you have a custom recovery installed.

Make sure your device has more than 50% battery.

DISCLAIMER

RootMyGalaxy.net is not responsible for any damage happened to your device(s) while following this guide, Proceed at your own risk.

Downloads

Download LineageOS 15.1 for Google Pixel 2 XL Download Official GApps For LineageOS 15.1 ROMs Download latest Magisk supports Android Oreo | Android 8.1 (If you want root access)

How to install LineageOS 15.1 on Google Pixel 2 XL | Android 8.1 Oreo

Make sure your device is rooted and have the latest TWRP recovery installed. (Check the Pre-Requirement Section Above) First, download the files from the above link. Now transfer the downloaded files to the internal storage of your device. Now reboot to the TWRP recovery by holding your power and volume down buttons together for a few seconds. Take a backup by selecting the option from the home screen and then your data and cache from the recovery menu.

Now select install and then browse for the downloaded ROM file and then select it. Next flash the Gapps file and then Magisk (optional).

Once the flashing process is completed, reboot your phone and you will be booted into LineageOS 15.1 Based on Android Oreo 8.1. If you have any doubts regarding this process, feel free to comment below. Source: XDA