In this post I aim to highlight my findings in deciding to go through the process of installing LineageOS on my Pixel 3a. Currently, LineageOS does not officially support the Pixel 3a. However, InvisibleK (Dan Pasanen) does host updated versions of his unofficial LineageOS build for the Pixel 3a complete with a custom recovery to utilize for this purpose!

Thank You

Before going on any further, I’d like to take a moment to give my sincere thanks to InvisibleK (Dan Pasanen). Having to set up the entire custom build for Pixel 3a of LineageOS myself would add far more overhead in the overall simple task in trying to get LineageOS to work on a Pixel 3a!

tl;dr

Preface

There are plenty of guides out there on how to install and set up ADB and Fastboot on your host machine. For me, on Arch Linux, this was as simple as running pacman -S android-tools. However, should you be on MacOS or Windows you may have to find resources on how to go about this. I do not intend to go over this here – sorry

Additionally, this guide also assumes the reader has some familiarity with ADB and/or Fastboot.

Source Files

If you, the reader, know what you’re doing and simply just require the files for your Pixel 3a they can be found here:

Installation

Warning!

If it isn’t abundantly clear by now, be aware that you will be destroying all the data currently on your Pixel 3a in the process of installing LineageOS on your device! Stop now and back up any files, 2FA codes, or other prior to proceeding.

Note about TWRP

As of writing this, TWRP1 (a custom recovery commonly used in custom OS installation) does not support Android 10. This would have been the preferred for a custom recovery, though not strictly required. Since we will be installing LineageOS 17.1 for Android 10 we cannot use TWRP.

Flash to Stock

Google is kind enough to provide a variety of versions of the stock images for the Pixel devices. In my process of installing LineageOS, as it will be on Android 10, I made sure to flash to the latest stock version of Pixel 3a Android 10. Do note that the versions are listed in reverse order, with the latest being found in the bottom-most row.

Additionally, Google provides a helper script flash-all that I highly recommend running as-is to flash your Pixel 3a to stock. This can take a few minutes to complete.

Flash Custom Recovery

Using InvisibleK’s build page, you’ll find the required custom recovery image for flashing found at the bottom of the list of zip files marked with a lone “download” link.

Flash it via the following steps:

  1. Reboot to recovery
    $ adb reboot bootloader
    
  2. Unlock the bootloader if the ‘Status’ is locked:
    $ fastboot flashing unlock
    
  3. Flash the custom recovery (make sure to replace N with the version you downloaded, mine was ‘4’)
    $ fastboot flash boot sargo-recovery-eng-N.img
    
  4. Boot the custom recovery either by re-entering recovery mode or fastboot – make sure to wait for it to enter Android Recovery after
    $ fastboot boot sargo-recovery-eng-N.img
    

Install LineageOS

Now that the custom recovery is set up and booted into, we’re ready to install LineageOS!

  1. Important! Once in recovery, ensure to Wipe data/factory reset prior to proceeding.
  2. Select Apply update from ADB
  3. ADB Sideload the version, if not latest, of LineageOS you want for your Pixel 3a
    $ adb sideload lineage-17.1-2020517-UNOFFICIAL-sargo.zip
    
  4. Wait for installation to complete then select ‘Reboot system now’ from the recovery menu
  5. Enjoy LineageOS!

Verification

Once in LineageOS, you can browse the settings to verify the installation and set up Trust the preferred way. Personally, I chose to leave the defaults.

Bugs / Issues

I plan to keep this list of bugs and issues I discover up to date, but this is what I have encountered so far:

  • WiFi calling does not seem to work

  1. Team Win Recovery Project ↩︎