https://9to5google.com/2022/08/19/android-13-flashing-pixel-6/
�oogle posts additional instructions for Pixel 6 owners that flashed Android 13

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.

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.

NewsKrawler wrote:

> í±‡oogle posts additional instructions for Pixel 6 owners that flashed Android 13

^^^
what's so tricky about a capital G?

<https://www.i18nqa.com/debug/utf8-debug.html>

> 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

Wouldn't it have been straightforward for them to immediately release 13.000001
so you have marginally different versions of 13 in the _a and _b slots?

Andy Burns <usenet@andyburns.uk> wrote:
> Wouldn't it have been straightforward for them to immediately release
> 13.000001 so you have marginally different versions of 13 in the _a and _b
> slots?

Does that actually help? If your phone is running 12.whatever and sees that
13.000001 is available, won't it decide to install that and leave
12.whatever in the other slot. In other words the 13.000001 strategy only
works for people who already downloaded 13.0, which may not be a huge number
depending on how aggressively 13.0 was pushed (many people don't upgrade to
a new release straightaway).

But if 12.whatever will no longer boot, the second slot is useless. So
maybe the installer has to replace that with 'something' that will boot, as
a fallback plan. I expect that's not something they immediately have
tooling for.

Theo

Theo wrote:

> Does that actually help? If your phone is running 12.whatever and sees that
> 13.000001 is available, won't it decide to install that and leave
> 12.whatever in the other slot.

Hi Andy or Theo,
I don't have a Pixel and I am (almost) completely unfamiliar with how it
updates (as compared to my phone which doesn't have A/B infrastructure).

Can you explain, in layman's terms, what happened with Android 13/Pixel6?

I get it that the "new" Android goes in slot B while the "old" Android is
sitting in slot A but that's just about all that I get.

In layman's terms, what happened here with the Pixel 6 & the 12->13 update?

On Sat, 20 Aug 2022 06:10:10 -0000 (UTC), NewsKrawler wrote:

> https://9to5google.com/2022/08/19/android-13-flashing-pixel-6/
> í±‡oogle posts additional instructions for Pixel 6 owners that flashed Android 13

Still waiting for the OTA image on my Pixel 6...

--
s|b

On 8/20/22 9:47 AM, Andy Burnelli wrote:
> In layman's terms, what happened here with the Pixel 6 & the 12->13 update?

The Pixel 6 platform bootloader for Android 13 increments a permanent
anti-rollback counter at the first successful boot of Android 13.

Much like blowing a bridge after you cross it, this prevents rolling back
the bootloader on the Tensor Pixel 6 series but not on previous Pixels.

The bridge is blown because of a critical security vulnerability in the
Android 12 bootloader. This also prevents loading older bootloader images.

When you update using the OTA method the Android 13 bootloader goes into
one A/B slot with Android 12 on the "old" slot. If Android 13 boots far
enough to blow the anti-rollback brodge but later fails and the device
recycles to the Android 12 slot, the device will fail to boot because the
Android 12 bootloader has now been locked out by the anti-rollback counter.

This doesn't affect Samsung devices is because Samsung has stubbornly
resisted the AOSP model and continues to use a standalone recovery
partition instead of the A/B format. The drawback to this is that the
system must go down for an extended period of time while the update is
installed in recovery, preventing use of the device during that time.
--
Jerry Friedman