12 ms·

Unlocking the Pixel 9 bootloader breaks some Pixel AI apps

91 points by edward 2y ago

glitchc 2y ago
Does it start working again if you re-lock the bootloader?
- flutas 2y ago
  Yes* * re-locking wipes your device to a factory state
  - glitchc 2y ago
    In that case it sounds like a software protection product has been applied to the AI-based applications. That product is doing a simple check that should be fairly easy to hypass through other means.
    - flutas 2y ago
      Nah, it's doing a server side check for the devices TEE keys before letting it launch the models. Something that, at least publicly, can't be bypassed. Even with something like TrickyStore to fake the TEE keys.
      - glitchc 2y ago
        A local phone reset won't touch the TEE keys though. It doesn't sound that sophisticated.
        flutas 2y ago
        Yeah, I should have said with rather than for. They're doing server side verification of the TEE environment using their protected download service from what I can tell. https://github.com/google/private-compute-services/tree/master/src/com/google/android/as/oss/pd https://github.com/google/private-compute-services/tree/mast...
  - SushiHippie 2y ago
    Not on GrapheneOS, you are able to re-lock it after installing GraphenOS (and you should), I think it just wipes the user data, but definitely not to a factory state
semi-extrinsic 2y ago
Sounds like a win-win scenario?
- complaintdept 2y ago
  Yeah I'm not seeing a downside to this.
  - fsflover 2y ago
    Until they start removing more features.
jsheard 2y ago
This isn't unprecedented, Sony used to encrypt most of their phones image processing stack with a key which was deleted forever if you unlocked the bootloader, making the camera permanently perform much worse even if you re-locked the bootloader later. Likewise with Winevine DRM, unlocking the bootloader will break L1 playback, either forever or until you re-lock depending on the device. I'm guessing this is Google similarly trying to stop people extracting their local models by not letting unlocked devices access them. I wonder if they'll also crack down on porting the Pixel Camera app to non-Pixel devices, people have been doing that forever because the processing is better than many devices native camera apps.
- treyd 2y ago
  That this is legal is crazy to me. Such a strong reason to split up the hardware and software sides of the businesses.
  - alphabettsy 2y ago
    Why would it be illegal? I’m not saying it’s right, but what would the law look like making it illegal and what would the impact be positive and negative?
    - bakugo 2y ago
      > Why would it be illegal for a manufacturer to retain full control of what you do on your device after they've supposedly sold it to you? The fact that this question even needs to be asked at all shows just how dire the state of consumer rights in tech is.
      - alphabettsy 2y ago
        Who’s asking that question?
        Dylan16807 2y ago
        It's a rephrasing of your question, isn't it? If there's a difference in this context, please clarify.
chimeracoder 2y ago
Unlocking the bootloader has long broken a lot of functionality. Play Integrity (formerly known as SafetyNet) provides three levels of checks, and increasingly apps are requiring the phone to pass the second level in order to use the app. Until last year, it was possible to spoof the second level (though not the third), with an unlocked bootloader, but Google started cracking down on that hard and it's essentially a game of whack-a-mole. Because the spoofing requires finding the fingerprint for a supported device that hasn't yet been banned (of which there are a finite number), it's a losing battle. That said, unlocking the bootloader on Pixel devices is less useful than it used to be, because of an expansion between what the base device already does and a degradation of what an unlocked and/or rooted device can do. There are fewer custom ROMs than there were a decade ago, and (unlocked) Pixel devices get rapid updates with long official support. Rooting the device used to give you the ability to install custom adblockers and bypass screenshot restrictions, but Android now has better support for DNS-based adblocking built in, and they've now cut off the main loopholes that allowed people to screenshot apps that block access. I think it's now impossible to screenshot an app if the app has blocked screenshots[0]. Ironically, it's easier to screenshot or get videos of apps on iOS than of those same apps on Android - I don't know if that's because developers don't bother to implement the blocking APIs on iOS or some other reason, but more than once I've ended up having to pull out a backup iPhone in order to screenshot/record something I couldn't on a Pixel device. Pixel phones already don't include most of the bloatware that comes with other devices, and the remaining stuff is built in and can't really be removed without impacting the core functionality of the device. So root access gets you a lot less than it used to, for Pixel devices. [0] In the spirit of classic bash, I am asserting that it's impossible, half hoping that someone will take that as an opportunity to correct me: https://web.archive.org/web/20230711000352/bash.org/?152037 https://web.archive.org/web/20230711000352/bash.org/?152037
- lofaszvanitt 2y ago
  Are you not allowed to take screenshots of specific apps? Not gonna buy this phone then :(.
  - treyd 2y ago
commercialnix 2y ago
I'll gladly finance at 4x the cost (so like around $5,000) to purchase an alternative Pixel for a fully open source bootloader with physically compartmentalized chips with open interfaces and a less sleek device. I don't give a shit about Ai slop.
- fsflover 2y ago
  Sounds a bit like Librem 5.
  - gkhartman 2y ago
    I wish it was comparable. The Librem 5 is years behind flagship smartphone hardware. I want to switch, but it would be difficult to give up the stability that comes with Android. That said, maybe the Librem has improved in the last year or so.
    - fsflover 2y ago
      > The Librem 5 is years behind flagship smartphone hardware. https://puri.sm/posts/the-danger-of-focusing-on-specs/ https://puri.sm/posts/the-danger-of-focusing-on-specs/ > but it would be difficult to give up the stability that comes with Android This is true: Android had a decade of development with a huge team. However, depending on your usage patterns, it can be good enough today. It works as my daily driver. See also: https://news.ycombinator.com/item?id=41356567 https://news.ycombinator.com/item?id=41356567
      - gkhartman 2y ago
        Thanks for the info. Their comments on hardware treadmills are reasonable. I'm not looking to chase the latest hardware, but I was still scared off by reviews claiming web video playback performance issues. I suppose I was hopping for the bumps to smooth out a bit. I find it encouraging to hear that it's working for you. I'll probably take another look at making the switch when I have a moment. I'd much rather support an alternative platform if possible.
codethief 2y ago
Is it just the unlocking or do those apps also look at the exact keys securing the boot chain & OS? In other words, what if I install GrapheneOS and lock the bootloader again?
- flutas 2y ago
  I've personally looked into the Pixel Screenshots check. It appears that they are doing server side verification of the devices TEE[1] keys plus bootloader checks, either of which will trip it. This can be spoofed using leaked keys (that get revoked fairly quick), but in this case it seems they are also verifying that the keys are the keys for their Pixel 9 devices. [1]: https://source.android.com/docs/security/features/trusty https://source.android.com/docs/security/features/trusty
  - privacyking 2y ago
    On a tangent, have you ever looked into the google phone app and how it decides whether it will offer call screening?
- DownrightNifty 2y ago
  I took a brief look into it, and they use the Google Private Compute Services Protected Download API to download the Gemini Nano model, which uses remote attestation to cryptographically ensure that your device is running the stock ROM: https://github.com/google/private-compute-services/tree/master/src/com/google/android/as/oss/pd https://github.com/google/private-compute-services/tree/mast... I'm not sure why they do that, tbh, since Gemini Nano is now part of Chrome, and you can download it without remote attestation. If you were dedicated enough, you could probably force the AICore system app on a rooted device into using the Gemini Nano model you downloaded from Chrome. I briefly attempted this but it proved too annoying so I gave up. Edit: It appears Pixel Screenshots works differently than Pixel Recorder, which is what I was looking into. https://news.ycombinator.com/item?id=41373011 https://news.ycombinator.com/item?id=41373011
rchaud 2y ago
> Pixel Screenshots [...] which lets you capture screenshots that are analyzed by Google’s Gemini Nano on-device AI and saved in a searchable index, allowing you to ask Google for information about things you saved days, weeks, or months ago.. Sounds like a benefit, to be honest. I take a lot of screenshots. It's never occurred to me to "ask Google" about something I screenshotted. I don't hoard screenshots, they're actively used for something, maybe an idea for a creative project, or a quote I liked. Once they're logged somewhere, I delete the screenshot, as it's no longer necessary. This feature also sounds suspiciously similar to Windows Recall.
LegitShady 2y ago
as long as it still does call screening im ok. the rest is AI hype garbage.
bitwize 2y ago
The "and nothing of value was lost" meme seems applicable here.
- fsflover 2y ago
  Until they start removing more features.
babra4151 2y ago
[dead]
deleted 2y ago
[deleted]
testitest1 2y ago
This is exactly the reason why Fairphone should increase their Hardware security comparable to the Titan M2 so that there is an environmentally friendly, secure alternative out there that support AS many custom Roms/OS AS possible.

91 points by edward 2y ago

glitchc 2y ago

Does it start working again if you re-lock the bootloader?

flutas 2y ago
Yes* * re-locking wipes your device to a factory state
- glitchc 2y ago
  In that case it sounds like a software protection product has been applied to the AI-based applications. That product is doing a simple check that should be fairly easy to hypass through other means.
  - flutas 2y ago
    Nah, it's doing a server side check for the devices TEE keys before letting it launch the models. Something that, at least publicly, can't be bypassed. Even with something like TrickyStore to fake the TEE keys.
    - glitchc 2y ago
      A local phone reset won't touch the TEE keys though. It doesn't sound that sophisticated.
      - flutas 2y ago
        Yeah, I should have said with rather than for. They're doing server side verification of the TEE environment using their protected download service from what I can tell. https://github.com/google/private-compute-services/tree/master/src/com/google/android/as/oss/pd https://github.com/google/private-compute-services/tree/mast...
- SushiHippie 2y ago
  Not on GrapheneOS, you are able to re-lock it after installing GraphenOS (and you should), I think it just wipes the user data, but definitely not to a factory state

semi-extrinsic 2y ago

Sounds like a win-win scenario?

complaintdept 2y ago
Yeah I'm not seeing a downside to this.
- fsflover 2y ago
  Until they start removing more features.

jsheard 2y ago

This isn't unprecedented, Sony used to encrypt most of their phones image processing stack with a key which was deleted forever if you unlocked the bootloader, making the camera permanently perform much worse even if you re-locked the bootloader later. Likewise with Winevine DRM, unlocking the bootloader will break L1 playback, either forever or until you re-lock depending on the device. I'm guessing this is Google similarly trying to stop people extracting their local models by not letting unlocked devices access them. I wonder if they'll also crack down on porting the Pixel Camera app to non-Pixel devices, people have been doing that forever because the processing is better than many devices native camera apps.

treyd 2y ago
That this is legal is crazy to me. Such a strong reason to split up the hardware and software sides of the businesses.
- alphabettsy 2y ago
  Why would it be illegal? I’m not saying it’s right, but what would the law look like making it illegal and what would the impact be positive and negative?
  - bakugo 2y ago
    > Why would it be illegal for a manufacturer to retain full control of what you do on your device after they've supposedly sold it to you? The fact that this question even needs to be asked at all shows just how dire the state of consumer rights in tech is.
    - alphabettsy 2y ago
      Who’s asking that question?
      - Dylan16807 2y ago
        It's a rephrasing of your question, isn't it? If there's a difference in this context, please clarify.

chimeracoder 2y ago

Unlocking the bootloader has long broken a lot of functionality. Play Integrity (formerly known as SafetyNet) provides three levels of checks, and increasingly apps are requiring the phone to pass the second level in order to use the app. Until last year, it was possible to spoof the second level (though not the third), with an unlocked bootloader, but Google started cracking down on that hard and it's essentially a game of whack-a-mole. Because the spoofing requires finding the fingerprint for a supported device that hasn't yet been banned (of which there are a finite number), it's a losing battle. That said, unlocking the bootloader on Pixel devices is less useful than it used to be, because of an expansion between what the base device already does and a degradation of what an unlocked and/or rooted device can do. There are fewer custom ROMs than there were a decade ago, and (unlocked) Pixel devices get rapid updates with long official support. Rooting the device used to give you the ability to install custom adblockers and bypass screenshot restrictions, but Android now has better support for DNS-based adblocking built in, and they've now cut off the main loopholes that allowed people to screenshot apps that block access. I think it's now impossible to screenshot an app if the app has blocked screenshots[0]. Ironically, it's easier to screenshot or get videos of apps on iOS than of those same apps on Android - I don't know if that's because developers don't bother to implement the blocking APIs on iOS or some other reason, but more than once I've ended up having to pull out a backup iPhone in order to screenshot/record something I couldn't on a Pixel device. Pixel phones already don't include most of the bloatware that comes with other devices, and the remaining stuff is built in and can't really be removed without impacting the core functionality of the device. So root access gets you a lot less than it used to, for Pixel devices. [0] In the spirit of classic bash, I am asserting that it's impossible, half hoping that someone will take that as an opportunity to correct me: https://web.archive.org/web/20230711000352/bash.org/?152037 https://web.archive.org/web/20230711000352/bash.org/?152037

lofaszvanitt 2y ago
Are you not allowed to take screenshots of specific apps? Not gonna buy this phone then :(.
- treyd 2y ago

commercialnix 2y ago

I'll gladly finance at 4x the cost (so like around $5,000) to purchase an alternative Pixel for a fully open source bootloader with physically compartmentalized chips with open interfaces and a less sleek device. I don't give a shit about Ai slop.

fsflover 2y ago
Sounds a bit like Librem 5.
- gkhartman 2y ago
  I wish it was comparable. The Librem 5 is years behind flagship smartphone hardware. I want to switch, but it would be difficult to give up the stability that comes with Android. That said, maybe the Librem has improved in the last year or so.
  - fsflover 2y ago
    > The Librem 5 is years behind flagship smartphone hardware. https://puri.sm/posts/the-danger-of-focusing-on-specs/ https://puri.sm/posts/the-danger-of-focusing-on-specs/ > but it would be difficult to give up the stability that comes with Android This is true: Android had a decade of development with a huge team. However, depending on your usage patterns, it can be good enough today. It works as my daily driver. See also: https://news.ycombinator.com/item?id=41356567 https://news.ycombinator.com/item?id=41356567
    - gkhartman 2y ago
      Thanks for the info. Their comments on hardware treadmills are reasonable. I'm not looking to chase the latest hardware, but I was still scared off by reviews claiming web video playback performance issues. I suppose I was hopping for the bumps to smooth out a bit. I find it encouraging to hear that it's working for you. I'll probably take another look at making the switch when I have a moment. I'd much rather support an alternative platform if possible.

codethief 2y ago

Is it just the unlocking or do those apps also look at the exact keys securing the boot chain & OS? In other words, what if I install GrapheneOS and lock the bootloader again?

flutas 2y ago
I've personally looked into the Pixel Screenshots check. It appears that they are doing server side verification of the devices TEE[1] keys plus bootloader checks, either of which will trip it. This can be spoofed using leaked keys (that get revoked fairly quick), but in this case it seems they are also verifying that the keys are the keys for their Pixel 9 devices. [1]: https://source.android.com/docs/security/features/trusty https://source.android.com/docs/security/features/trusty
- privacyking 2y ago
  On a tangent, have you ever looked into the google phone app and how it decides whether it will offer call screening?
DownrightNifty 2y ago
I took a brief look into it, and they use the Google Private Compute Services Protected Download API to download the Gemini Nano model, which uses remote attestation to cryptographically ensure that your device is running the stock ROM: https://github.com/google/private-compute-services/tree/master/src/com/google/android/as/oss/pd https://github.com/google/private-compute-services/tree/mast... I'm not sure why they do that, tbh, since Gemini Nano is now part of Chrome, and you can download it without remote attestation. If you were dedicated enough, you could probably force the AICore system app on a rooted device into using the Gemini Nano model you downloaded from Chrome. I briefly attempted this but it proved too annoying so I gave up. Edit: It appears Pixel Screenshots works differently than Pixel Recorder, which is what I was looking into. https://news.ycombinator.com/item?id=41373011 https://news.ycombinator.com/item?id=41373011

rchaud 2y ago

> Pixel Screenshots [...] which lets you capture screenshots that are analyzed by Google’s Gemini Nano on-device AI and saved in a searchable index, allowing you to ask Google for information about things you saved days, weeks, or months ago.. Sounds like a benefit, to be honest. I take a lot of screenshots. It's never occurred to me to "ask Google" about something I screenshotted. I don't hoard screenshots, they're actively used for something, maybe an idea for a creative project, or a quote I liked. Once they're logged somewhere, I delete the screenshot, as it's no longer necessary. This feature also sounds suspiciously similar to Windows Recall.

LegitShady 2y ago

as long as it still does call screening im ok. the rest is AI hype garbage.

bitwize 2y ago

The "and nothing of value was lost" meme seems applicable here.

fsflover 2y ago
Until they start removing more features.

babra4151 2y ago

[dead]

deleted 2y ago

[deleted]

testitest1 2y ago

This is exactly the reason why Fairphone should increase their Hardware security comparable to the Titan M2 so that there is an environmentally friendly, secure alternative out there that support AS many custom Roms/OS AS possible.