When the Android Nexus released, we talked about all types of new features. We’ve got a new renewal user interface to launch long-term Multi-MID capabilities and Volcan Graphics APIs as well. But a minimal interest was full of additional consumer heads. Android nigrate introduced “smooth updates” which support devices / A distribution. At present Android Audiences (besides Google Google Plus and Google Pixel XL), the A / B was not split and thus could not afford smooth updates. The basic basis for this feature is that the device is a second set of systems, boats, sellers and other key parts, and when you get OTA updates, it is in the background while the other part is divided into the other part. happens. You make random backups of backup updates. If an update fails, you will have to return to a working building, meaning that there may be less headaches to deal with companies and consumers are better secure.


Unlike project trials, it is not necessary to support smooth updates for any new Android device. In this way, the majority of new android devices does not support feature. We are still keeping a list of all the auxiliary devices, and it is clear that this feature is not widely supported. It is a shame because A / B parties have to take advantage of both regular and consumer users. However, feature is a little bit of a bit of solidarity in the encouraged community because it makes it easier for Android to develop and flash. This is not actually the case, so we want to ignore smooth updates and explain how the XDA is affected by the custom development on the A / B distribution.


Thank you very much for the XDA Senior Member, N. G. Jasonson, a partner of Lenjeise and Motorola Hot Z2 Force, who used to help us investigate this article.

Distributed on an Android device

A split is only a small part of the phone’s internal storage where data is kept. What kind of data is placed on each distribution depends on the hardware, operating system, and many other factors. The boot loader will be the same, one must have the system (Android OS), a user’s data … and so on. When you talk about people “/ system” and “/ cash”, they refer to the names given for these divisions. One plus 6, for example, is 72 split. It feels a lot, but WinPlus 6 is one of these devices

There is a lot of distribution on a device that you will not worry about the user. While editing custom ROMs, pages, receipts, or Magas or Xposed, many of these divisions are never modified. Many of these divisions will be unused for our purposes or are very dangerous in touch unless you know what you are doing (XLOADER and OEMINFO are coming to mind on Household / Honorage devices.) Android users’ distribution is that we often have systems, boots, recovery, user data and more recently promoted and vbmeta. Here is a brief statement of the purpose of each division:

System – Android OS, system libraries, system apps, and other system such as bootanimations, stock wallpapers, ringtones, etc.
Boat – also retains Danias, Ramdesk, and A / B devices
Recovery – Maintenance space, where TWRP is spread over most common devices (A / B devices do not have a break-off distribution)

userdata – keeps all your apps, systems, and internal storage data
Vendor – Keeps platform and device-specific HAL, essential files for Android OS to communicate with basic hardware
VBmeta – Boots distributed for Android validation boot 2.0, which validates the integrity of the boot process
Device OEMs can use their distribution plans to customize them. For example, Hawwa boot divides the division into ramdisk_recovery and Dana. It also includes a lot of extra splits that may contain other system apps, such as protectors, products and disciplines, and when it is safe to save, it is generally not recommended if the stock is returned. You want to simplify yourself. So A / B domains play a role?

A / B distribution plan

How to update updates on devices with smooth updates

I illustrate a simple picture below how to update the device with A / B distribution support. Distributing distribution system is divided, although any OEM can be updated as boot and vendor, as well as the update of any OTA. This update process not only works with the latest Android version updates but also a security patch update.

We start with two systems on the same version of Android, system_a and system_b.
Let’s assume that system_a is active, OTA update system_b will pass, ineffective distribution in the background.
System_a is disabled and set to system_b then the user becomes active after the reboot More.