Seamless updates, first introduced back in 2016 and showed up on every Google Pixel phone, enables firmware updates to be installed to a secondary partition while the phone stays in usage. This gets rid of downtime between firmware updates to a single reboot, after which the secondary partition ends up being the main one and the upgrade has already finished. This also acts as a failsafe in case an update fails– the system can fall back on the previous partition.
Update alert on a Samsung Galaxy S21 Ultra
Google has backed off on this requirement since its no longer in the Android CDD (Compatibility Definition Document). The CDD serves as a standard for Android OEMs and lists what Google needs from OEMs for their gadgets to be compatible with the newest variation of Android.
Without smooth updates, an Android device will need to invest a number of minutes of downtime on a bootloader screen, without the ability to use any applications or make any telephone call, even of the emergency situation kind. Samsungs thinking for postponing such a feature is unknown.
Its presumed that the requirement was backed off by pressure from OEMs like Samsung, whos latest Galaxy S21 mobile phones do not have the framework to support seamless updates. The “a” and “b” refer to the identical partitions that alternate in between firmware updates.
Source – Via