Upgrade LineageOS on Xiaomi Redmi S2 / Y2

Manually upgrading LineageOS (to higher LineageOS version)

Note

The updater app does not support upgrades from one version of LineageOS to another, and will block installation to any update for a different version. Upgrading manually requires similar steps to installing LineageOS for the first time.

Warning

If you previously had a Google Apps add-on package installed on your device, you will need to install an updated package before booting Android for the first time! If you did not have Google Apps installed, you will need to wipe the Data partition (or perform a factory reset) to install it. The updated Google Apps add-on package can be found here (use the arm64 architecture).

Go to the Download Portal and download the newest version.
Reboot your device into recovery mode by holding the appropriate key combination.
On the Lineage Recovery home screen, tap Apply update, then Apply from ADB for starting the sideload service.
Open a ADB & Fastboot tools window on your PC and flash the LineageOS install package you downloaded before:

$ adb sideload lineage-21.0-xxxxxxxx-UNOFFICIAL-ysl.zip

Note

After the package is installed, recovery will may inform you that reboot to recovery is required to install add-ons. In case you want to do that, please select Yes, otherwise No.

Installing Add-Ons

Note

If you don’t want to install any add-on (such as Google Apps), you can skip this whole section!

On the Lineage Recovery home screen, tap Apply update, then Apply from ADB for starting the sideload service.
Open a ADB & Fastboot tools window on your PC and flash the LineageOS install package you downloaded before:

$ adb sideload add-on.zip

Note

When presented with a screen that says Signature verification failed, click Yes. It is expected as add-on packages aren’t signed with the same keys!

All set!

On the Lineage Recovery home screen, tap Reboot system now.
If everything went well, you will be greeted by the infamous LineageOS boot animation :D.