***Note: THIS IS NOT A ROOT GUIDE. For updating and root instructions, check out my guide here.***
From the Pixel Images page:
This applies to ALL Tensor devices, regardless of whether or not you're rooted!
What this means:
Once Android 13 Stable boots, it updates an anti-rollback counter in the device hardware to prevent rolling back the bootloader. This will prevent previous versions of the bootloader from starting.
Why this is a problem:
The OTA only updates one slot, then reboots into that slot. It does not update both slots at once. If there is a boot failure after updating to Android 13, the device may attempt to "recycle" back to the old slot. If this other slot has a previous version of the bootloader, the bootloader will not start, rendering the device a brick.
How do I make sure this doesn't happen to me?
If you updated via OTA, simply sideload the OTA again. Since you are currently on the Android 13 slot, this will overwrite your old Android 12 slot with the new bootloader.
If you have an unlocked bootloader and prefer to update using the factory image, you can flash the bootloader to both slots:
I've updated several times since the August 2022 update, am I still at risk?
If you've updated via OTA at least once since you first updated to Android 13, you should be fine. Instructions to check bootloader versions are further down this post.
The initial Android 13 release bootloader version is slider-1.2-8739948. As long as your bootloader is equal to or higher than this, you should be fine.
What if I was on the Android 13 Beta?
Same as above - the beta did not incorporate the anti-rollback, and the beta bootloaders are still considered "old".
Will the new bootloader prevent me from flashing and running Android 12?
The short answer is YES. Android 12 will not run properly on the Android 13 bootloader. Contrary to what the warning above says, you CAN flash Android 12 on the Android 13 bootloader, and though it will boot, it will not run properly. See this post.
If you MUST use Android 12, you can use a Developer Support Image.
How do I check my current bootloader version?
From the Pixel Images page:
This applies to ALL Tensor devices, regardless of whether or not you're rooted!
What this means:
Once Android 13 Stable boots, it updates an anti-rollback counter in the device hardware to prevent rolling back the bootloader. This will prevent previous versions of the bootloader from starting.
Why this is a problem:
The OTA only updates one slot, then reboots into that slot. It does not update both slots at once. If there is a boot failure after updating to Android 13, the device may attempt to "recycle" back to the old slot. If this other slot has a previous version of the bootloader, the bootloader will not start, rendering the device a brick.
How do I make sure this doesn't happen to me?
If you updated via OTA, simply sideload the OTA again. Since you are currently on the Android 13 slot, this will overwrite your old Android 12 slot with the new bootloader.
If you have an unlocked bootloader and prefer to update using the factory image, you can flash the bootloader to both slots:
fastboot flash bootloader --slot=all <bootloader image> It's highly recommended you do this BEFORE updating, but if you didn't, do it as soon as possible.I've updated several times since the August 2022 update, am I still at risk?
If you've updated via OTA at least once since you first updated to Android 13, you should be fine. Instructions to check bootloader versions are further down this post.
The initial Android 13 release bootloader version is slider-1.2-8739948. As long as your bootloader is equal to or higher than this, you should be fine.
What if I was on the Android 13 Beta?
Same as above - the beta did not incorporate the anti-rollback, and the beta bootloaders are still considered "old".
Will the new bootloader prevent me from flashing and running Android 12?
The short answer is YES. Android 12 will not run properly on the Android 13 bootloader. Contrary to what the warning above says, you CAN flash Android 12 on the Android 13 bootloader, and though it will boot, it will not run properly. See this post.
If you MUST use Android 12, you can use a Developer Support Image.
How do I check my current bootloader version?
Code:
adb reboot bootloader #Reboots device to bootloader.
fastboot getvar current-slot #Outputs current slot, should also be visible on the device screen: "Boot slot"
fastboot getvar version-bootloader #Outputs current slot's bootloader version, should also be visible on device screen "Bootloader version"
fastboot --set-active=a or b #Use this to switch to the inactive slot - if current slot is A, set to B or vice versa.
fastboot getvar current-slot
fastboot getvar version-bootloader
fastboot --set-active=b or a (set to original slot) #Set active slot back to what it was before. If you started on slot A, make sure you switch back to slot A.
fastboot getvar current-slot
fastboot continue #Commands device to resume boot, same function as selecting "Start" in the bootloader menu.
#So as an example:
fastboot getvar current-sot
>current-slot: a
fastboot getvar version-bootloader
>version-bootloader: slider-1.2-8739948
fastboot --set-active=b
>Setting current slot to 'b'
fastboot getvar version-bootloader
>version-bootloader: slider-1.2-8739948
fastboot --set-active=a
>Setting current slot to 'a'
fastboot continue
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