[Google Pixel Guides, News, & Discussion] birdman59:
Pixel 32GB AND Pixel 128GB - I have loaded and tested these instructions at least ten successful times on each of these phones.

If at any time you get a failure or the phone does a long buzz/vibrate START OVER!

. I started over & went back to default Factory Settings at least a dozen times on each phone without any issues.

Prerequisites:

•	Google Pixel (sailfish) with Android 9.0

•	Phone unlocked

•	ADB installed and working on your PC

•	Download to PC: latest Lineage Nightly 16.0 zip, Nano GAPPS zip, and TWRP-3.3.1-0 image (not zip)

The Pixel Phone has two partitions, called Slot A and Slot B. There are many links out on the web talking about partitions and slots. It is very confusing, but once you get this phone up and working it is designed to do updates automatically. If a problem occurs with a new update the phone will revert back to the working slot/partition. Due to this dual partition architecture there is currently no a way to install TWRP to the phone so each time you need it you have to boot the image from bootloader. I have tried a hundred ways to make it work, but this seems to be the new norm for dual partition phones.

Turn phone off.

Load boot loader – Hold Pwr Button + VolumeDown at same time until you see the bootloader Start Menu

Select “Recovery Mode” (this will bring you to the Default Lineage Recovery Screen, NOT TWRP!!!!)

Select “Factory Reset”

Select “Wipe system” and click yes to continue

Select “Wipe data / factory reset” and click yes to continue

Go back to main Recovery Screen and select “Advanced” then “Power Off”

Load boot loader – Hold Pwr Button + VolumeDown at same time until you see the bootloader Start Menu

Loading TWRP – From PC at adb prompt type: fastboot boot <twrpfilename>.img ----NOTE: Only tested TWRP Version 3.3.1-0. Currently I believe this is the first version that handles dual partitions correctly.

Phone will load to the TWRP main menu.

From the Reboot Button ensure slot b is active: “Current: Slot b” If not change!

Go back to Advanced tab and click “ADB Side load”

From PC at adb prompt type: adb sideload <lineagenightlyfilename>.zip (this will take about 5 minutes)

Go back and click “Reboot”. Set slot A active: “Current: Slot a”

Go back and click “Reboot” and select “Recovery” NOTE: leave TWRP check boxes as is!

Select “Apply update”

Select “Apply from ADB”

From PC at adb prompt type: adb sideload <gappsfilename>.zip (my preference is nano gapps & the only one I tested) . NOTE: most likely you will get a warning the file is not signed – just click “Yes”

From main default Recovery Screen click “Reboot”

After a few minutes your phone should be booted to the “Hi” screen. Continue and click on “Start”.

For now skip connecting WiFi

Leave Google Services as Default (you can change all this later if you want)

Skip Fingerprint (can add it later)

Skip Pin (can add it later)

Lineage OS Features – Leave Stock/Default and click Next

Click Start

Enable one WiFi connection (add other WiFi connections later)

Enable Development Mode: Setting -> About Phone -> tap “Build Number” about seven times until it says enabled.

Enable USB Debugging: Setting -> System -> Advanced -> Developer Options -> click “Android Debugging” on.

Add Google Account in Settings -> Accounts -> add your google account

Go to Play Store and add any apps you want.

NOTE: if you get/see “Data Transfer Tool Keeps Stopping” message pop up DO NOT close the window, rather click on “App Info” and click “Uninstall”. Everything should load fine from this point.

*** SUCCESS – WORKING PHONE! ***

A lot of steps here, but I have tried many, many configurations/attempts with “slot a” and “slot b” and the directions above are the only ones I can consistently repeat.