With Android 13, Google made it so that the Pixel 6, 6 Pro, and 6a cannot reinstall Android 12 in order to address a security issue. In addressing that vulnerability, another problem might arise, and Google has released instructions on how to avoid bricking your device if you flashed Android 13.

What’s different with the Android 13 update for Pixel 6

A security vulnerability exists with the previous bootloader on the Pixel 6 series, and Android 13 makes it so that the vulnerable version associated with Android 12 cannot be reinstalled. 

However, even after flashing an Android 13 factory image – which is different than sideloading an OTA image – on the Pixel 6 series and successfully updating, an Android 12 build remains on your phone. This is due to Android’s A/B (seamless) system updates, which are meant to provide redundancy:

A/B system updates use two sets 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 are not accessed by the running system during normal operation. This approach makes updates fault resistant by keeping the unused slot as a fallback: If an error occurs during or immediately after an update, the system can rollback to the old slot and continue to have a working system.

As such, the “inactive slot contains an older bootloader whose anti-rollback version has not been incremented.” That mismatch can cause problems if you flash your device and something fails with the install. By design, Android will try booting from the inactive slot, but that runs afoul of the vulnerability protection. Given it’s Android 12 (and the older bootloader), your phone will not turn on. 

If you flashed Android 13

Google on Thursday afternoon provided instructions on how to avoid that particular issue from arising. It involves flashing the inactive slot from Android 12 to Android 13. The simplest option is sideloading an OTA image – which updates the inactive slot – but steps for using factory images are also provided.

This process is primarily aimed at those (i.e. tinkerers) who are going to reflash their devices either with a factory or custom image (built from AOSP). 

Meanwhile, Google in the coming days will update the Android Flash Tool – which flashes the active slot, like fastboot – with a prompt to flash the inactive slot with the Android 13 bootloader. 

If you used the Android 13 OTA

Those who sideloaded — a process with no device/data wipe — an Android 13 OTA image or accepted the on-device OTA (which is Google’s recommended install method) and don’t intend to flash (again, different from sideloading) their phones “don’t need to take any action for now.”

Slot A Slot B
Android 12 (July sec patch) Android 12 (June)
Android 12 (July) Android 13 (August)
Android 13 (September) Android 13 (August)
The active slot is in bold, with OTAs installing in the inactive slot

The company also tells us that there’s a very low chance of running into the issue for the overwhelming majority of users with locked bootloaders. The next OTA (presumably the September security patch) or sideload will update the inactive slot.

Kyle Bradshaw and Dylan Roussel contributed to this article.

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Abner Li

Editor-in-chief. Interested in the minutiae of Google and Alphabet. Tips/talk: abner@9to5g.com