Originally known as (introduced by Google with Android 7.0 Nougat), the AB system partition scheme is a design architecture that maintains two distinct copies of the firmware: Slot A and Slot B .
This is the "Multiboot" aspect: two distinct system images exist simultaneously. You don't choose which to boot via a menu (usually), but rather via a command or a failed boot attempt. ab multiboot
An A/B system typically partitions storage into at least two complete sets of critical partitions. Originally known as (introduced by Google with Android 7
Warning: Different ROMs share the same userdata partition. Booting a different ROM on the other slot may crash due to data incompatibility. An A/B system typically partitions storage into at
For modders, VABC is even harder to work with because you cannot simply flash raw images to inactive slots; you must use adb snapshot-update .
This guide dives deep into the nuts and bolts of AB multiboot, explaining how it works, why it replaced the old recovery system, and how you can leverage it to run multiple operating systems on a single device.