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+.. SPDX-License-Identifier: GPL-2.0+
+
+Android A/B updates
+===================
+
+Overview
+--------
+
+A/B system updates ensures modern approach for system update. This feature
+allows one to use two sets (or more) of partitions referred to as slots
+(normally slot A and slot B). The system runs from the current slot while the
+partitions in the unused slot can be updated [1]_.
+
+A/B enablement
+--------------
+
+The A/B updates support can be activated by specifying next options in
+your board configuration file::
+
+    CONFIG_ANDROID_AB=y
+    CONFIG_CMD_AB_SELECT=y
+
+The disk space on target device must be partitioned in a way so that each
+partition which needs to be updated has two or more instances. The name of
+each instance must be formed by adding suffixes: ``_a``, ``_b``, ``_c``, etc.
+For example: ``boot_a``, ``boot_b``, ``system_a``, ``system_b``, ``vendor_a``,
+``vendor_b``.
+
+As a result you can use ``ab_select`` command to ensure A/B boot process in your
+boot script. This command analyzes and processes A/B metadata stored on a
+special partition (e.g. ``misc``) and determines which slot should be used for
+booting up.
+
+Command usage
+-------------
+
+.. code-block:: none
+
+    ab_select <slot_var_name> <interface> <dev[:part_number|#part_name]>
+
+for example::
+
+    => ab_select slot_name mmc 1:4
+
+or::
+
+    => ab_select slot_name mmc 1#misc
+
+Result::
+
+    => printenv slot_name
+    slot_name=a
+
+Based on this slot information, the current boot partition should be defined,
+and next kernel command line parameters should be generated:
+
+* ``androidboot.slot_suffix=``
+* ``root=``
+
+For example::
+
+    androidboot.slot_suffix=_a root=/dev/mmcblk1p12
+
+A/B metadata is organized according to AOSP reference [2]_. On the first system
+start with A/B enabled, when ``misc`` partition doesn't contain required data,
+the default A/B metadata will be created and written to ``misc`` partition.
+
+References
+----------
+
+.. [1] https://source.android.com/devices/tech/ota/ab
+.. [2] https://android.googlesource.com/platform/bootable/recovery/+/refs/tags/android-10.0.0_r25/bootloader_message/include/bootloader_message/bootloader_message.h