Anti-rollback implications with older OS

DeletedUser622

Would it be technically feasible to install an older build of GOS on a Pixel 6a and re-lock the bootloader without bricking the device?

zache

DeletedUser622 Yes, though the bootloader unlock/relock will still wipe all user data if you're trying to avoid that.

DeletedUser622

zache Do not care about the data.

Blastoidea

Just out of vulgar curiosity, why do you want to do that?

I hope the question isn’t inappropriate.

DeletedUser622

Blastoidea For whatever reason, actually. I don't intend to install an older release, but I read here and there about the anti-rollback induced bricks and I'm willing to find the truth out. Like installing stock Pixel OS after an Alpha channel GOS has been installed etc. It makes me feel uncomfortable if there was indeed such limitation to return to an older version of Android on the device I own.

Blastoidea

DeletedUser622

What specifically, is desirable to you about an older version?

raccoondad

DeletedUser622 anti-rollback induced bricks

It won't brick your device, the older update will just not by applied and if it was manually written to the SSD somehow, the device would fail to boot and you would need to reinstall GOS.

"It makes me feel uncomfortable if there was indeed such limitation to return to an older version of Android on the device I own."

Why would a pretty clear security feature make you uncomfortable? Especially knowing the device can still be unlocked at any time. Anti-rollback is a basic feature. If you truly don't want it, disable boot locking

DeletedUser622

Blastoidea Not to me in particular. But I felt sad when I had learned of these limitations. I was eager to get clear about them, that's why I asked here.

Blastoidea

Okay

Blastoidea

raccoondad

That’s what I wondered, but I gave up.

DeletedUser622

raccoondad Why would a pretty clear security feature make you uncomfortable?

It is about exercing ownership over device I'm supposed to own. If I'm not allowed to install something older for whatever reason, mostly "because I want it so", the ownership is incomplete.

raccoondad Especially knowing the device can still be unlocked at any time.

That's what I wasn't sure about, hence the question.

Johnnyloans

DeletedUser622 If I'm not allowed to install something older for whatever reason, mostly "because I want it so", the ownership is incomplete.

You might by going to stock, google android then an old version of GOS.

userofgos

DeletedUser622 It is about exercing ownership over device I'm supposed to own. If I'm not allowed to install something older for whatever reason, mostly "because I want it so", the ownership is incomplete.

So you'd be okay with a threat actor installing an older exploitable version of your OS so they could "own" your device?

Not me, no thank you. This security feature + GrapheneOS enables me to "own" my device without worry that an adversary could "own" it as well.

DeletedUser622

userofgos So you'd be okay with a threat actor installing an older exploitable version of your OS so they could "own" your device?

But they cannot unless the bootloader is unlocked again which would imply the lost of data.
My question was about installing an older version regardless of the data with point not to get bricked after re-locking bootloader.

userofgos Not me, no thank you. This security feature + GrapheneOS enables me to "own" my device without worry that an adversary could "own" it as well.

It reminds me of essential Liberty vs little temporary Safety. But I respect your opinion.

userofgos

DeletedUser622 But they cannot unless the bootloader is unlocked again which would imply the lost of data.

I was referring to if/when anti-roll back protection is/was not in place, a threat actor could roll you back to an exploitable version of the OS and maintain the data on it