How to Completely Disable ‘Seamless Updates’ (A/B System Updates) System-Wide on Android

Seamless Updates (also known as A/B System Updates) is a prominent Android feature that allows the operating system to download and install OTA (Over-The-Air) updates to an inactive partition in the background while you continue using the device. Upon the next reboot, the phone simply switches to the updated partition. While highly convenient, this architecture permanently consumes a significant portion of internal storage space by maintaining two copies of the OS partitions. For power users on devices with limited storage, or enterprise administrators who want strict manual control over when updates apply via fastboot, disabling the A/B update mechanism may be desired.

This guide outlines the steps to completely disable Seamless Updates (A/B partitioning) on an Android device. Warning: This process requires an unlocked bootloader, wiping the device, and advanced command-line knowledge.

Prerequisites

You cannot simply toggle a switch in Settings to disable this. It requires re-flashing the device.

• An unlocked bootloader (which wipes user data).
• A PC with ADB and Fastboot installed.
• The factory image for your specific Android device.

How to Disable Seamless Updates via Fastboot

To strip the A/B functionality, you must wipe the dual partitions and force the device to boot from a single slot.

1. Connect your Android device to your PC and reboot into the bootloader/fastboot mode (usually by holding Power + Volume Down during restart).
2. Open a terminal or command prompt on your PC.
3. Ensure your device is recognized by typing: fastboot devices.
4. You must erase the secondary slots. Type the following commands, pressing Enter after each:

   fastboot erase boot_b
   fastboot erase system_b
   fastboot erase vendor_b

   (You may need to erase additional _b partitions depending on your device’s specific architecture).
5. Next, force the active slot to slot A:

   fastboot --set-active=a

6. You will now need to manually flash the factory image directly to the ‘a’ slot rather than relying on the standard flash-all script, which may attempt to write to both slots or re-enable the A/B configuration.

Important Considerations

Disabling Seamless Updates breaks the standard OTA update mechanism provided by the manufacturer. Once disabled, you will not be able to install updates via the Settings app; all future system updates must be sideloaded manually via ADB or Fastboot. Furthermore, you lose the failsafe protection that Seamless Updates provides (if an update fails on slot B, the phone simply boots back into the working slot A).