A thread (9 tweets) providing an overview of the overall update system on modern Android devices:
Quote Tweet
Replying to @piz_aza @knurd42 and @linmobblog
Modern Android uses block-based A/B updates for the firmware and OS images. Updates to firmware and the OS are installed to the alternate set of partitions while the OS is booted. Most updates are incremental (delta) updates where new images are generated from the existing ones.