‘Continuous updates’, first introduced in 2016 and arrived on all Google Pixel phones, allow firmware updates to be installed on a secondary partition while the phone remains in use. This eliminates downtime between firmware updates for a single reboot, after which the secondary partition becomes the primary partition and the update has already been completed. This also works as a fail-safe system in case an update goes wrong – the system can return to the previous partition.
Update notification on a Samsung Galaxy S21 Ultra
Google dropped this requirement as it is no longer on the Android CDD (Compatibility Definition Document). The CDD acts as a guideline for Android OEMs and lists what Google requires of OEMs in order for their devices to be compatible with the latest version of Android.
The requirement is presumed to have been disproved by pressure from OEMs like Samsung, whose latest Galaxy S21 smartphones have no structure to support continuous updates. Android Police confirmed that the new Samsung Galaxy S21 Ultra does not support the feature. Although Google previously planned the need for the feature, it is now mentioned in the CDD that OEMs “MUST” support a / b system updates. “A” and “b” refer to identical partitions that alternate between firmware updates.
Without continuous updates, an Android device will need to spend several minutes of inactivity on a bootloader screen, without the ability to use any apps or make calls, even the type of emergency. Samsung’s reason for postponing this feature is unknown.
Source • Via