Basic requirements

  1. Make sure your computer has working adb and fastboot. Setup instructions can be found here.
  2. Enable USB debugging on your device.

Unlocking the bootloader

  1. On the device, dial *#*#7378423#*#* (*#*#SERVICE#*#*) to launch the service menu.
  2. Go to service info > configuration and check rooting status - you can only continue if it says Bootloader unlock allowed: Yes.
  3. Connect the device to your PC via USB.
  4. On the computer, open a command prompt (on Windows) or terminal (on Linux or macOS) window, and type:
    adb reboot bootloader
    

    You can also boot into fastboot mode via a key combination:

    • With the device powered down, hold Volume Up and connect the USB cable. The notification light should turn blue.
  5. Once the device is in fastboot mode, verify your PC finds it by typing:
    fastboot devices
    
  6. Follow the instructions on Sony’s official unlocking website to unlock your bootloader.
  7. Since the device resets completely, you will need to re-enable USB debugging to continue.

Installing a custom recovery using fastboot

  1. Download a custom recovery - you can download TWRP.

  2. Connect your device to your PC via USB.
  3. On the computer, open a command prompt (on Windows) or terminal (on Linux or macOS) window, and type:
    adb reboot bootloader
    

    You can also boot into fastboot mode via a key combination:

    • With the device powered down, hold Volume Up and connect the USB cable. The notification light should turn blue.
  4. Once the device is in fastboot mode, verify your PC finds it by typing:
    fastboot devices
    
  5. Flash recovery onto your device:
    fastboot flash recovery twrp-x.x.x-x-sumire.img
    
  6. Now reboot into recovery to verify the installation:
    • With the device powered down, hold the Volume Down and Power buttons.

Installing LineageOS from recovery

  1. Download the LineageOS install package that you’d like to install or build the package yourself.

    • Optionally, download additional application packages such as Google Apps (use the arm64 architecture).
  2. If you aren’t already in recovery, reboot into recovery:
    • With the device powered down, hold the Volume Down and Power buttons.
  3. (Optional, but recommended): Tap the Backup button to create a backup. Make sure the backup is created in the external sdcard or copy it onto your computer as the internal storage will be formatted later in this process.
  4. Go back to return to main menu, then tap Wipe.
  5. Now tap Format Data and continue with the formatting process. This will remove encryption as well as delete all files stored on the internal storage.
  6. Return to the previous menu and tap Advanced Wipe.

  7. Select the Cache and System partitions to be wiped and then Swipe to Wipe.

  8. Sideload the LineageOS .zip package:
    • On the device, select “Advanced”, “ADB Sideload”, then swipe to begin sideload.
    • On the host machine, sideload the package using: adb sideload filename.zip
  9. (Optional): Install any additional packages using the same method.

  10. (Optional): Root the device by installing the LineageOS SU Addon (use the arm64 package) or using any other method you prefer.

  11. Once installation has finished, return to the main menu, tap Reboot, and then System.

Get assistance

If you have any questions or get stuck on any of the steps, feel free to ask on our subreddit or in #LineageOS on freenode.