One of the headlining features of the Android 7.0 Nougat update as well as the Google Pixel and Google Pixel XL is the ability to seamlessly install system updates. This feature from Android Nougat takes some of the pain away from updating your device and also reduces the likelihood of an inactive device.
Seamless System Updates are also known as A/B system updates, which have the goal of ensuring a workable booting system remains on the disk during an OTA update. Users can continue to use the device during the OTA update process as the only downtime during an update will be when the device reboots into the updated system. This is made possible as the update is installed in a different disk partition, and the bootloader then boots the device into the newly updated disk partition.
In A/B updates, the OS will make a few attempts to boot into the partition with the new update. But in case of continued failure, the device will ultimately reboot back from the older partition and older images. This failsafe ensures that at least one bootable image is present on the device, meaning less re-flashes and device replacements when things go horribly wrong.
A set of commits to the CMUpdater found in LineageOS points that this functionality will soon be available on the ROM.
CMUpdater: support A/B style OTA updates * Autodetect the type of zip (A/B OTA or traditional) * Handle A/B OTAs via UpdateEngine and display progress to the user.
Before you get too excited, A/B style OTA updates will only be available to a select few devices, namely the Google Pixel and Google Pixel XL. Older devices which were not launched with A/B style OTA support in their stock ROMs will lack the requisite partitions to support this new style of OTA. So, even though LineageOS will add in this functionality to their Updater, your device will not support it if it did not previously.
The commit has been merged into the LineageOS repo and should be making its way to the next nightly.
Have you had a chance to experience seamless system updates on your Pixel/Pixel XL? Let us know in the comments below!Source: LineageOS Review