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I have my daughter's Pixel 1 set up with Family Link. It should be running Android 10 I believe.

Recently I changed her screen lock password via my linked Parent Phone. I forgot to tell her and since she usually logs in using her fingerprint, she didn't notice the change until she had to restart her phone a month later, which enforces unlocking with her password.

Unfortunately, I forgot the new password in the meantime. If I see this correctly,

  • I cannot unlock the phone using my Parent Account after the reboot, right?
  • Also, since the phone has not fully booted without the initial unlock, I cannot change the password using the Family Link app because that has not started yet. I mean, I can change the password on my, it just doesn't change anything on hers.

I tried the suggestion here: How to reset a kid's forgotten phone lock-screen password?, but my daughter's phone does not have Find My Device installed.

Any ideas? The last resort would be to factory reset but I would like to avoid data loss. I think I had the phone set up for Developer Options last time I was able to access it. So if there is a way to do it with ADB or something I might try that although I would like to avoid the installation trouble if there is another way.

It would already help me to verify whether I am right in assuming that the initial boot unlock runs before the Family Link app or whether I may have made a mistake somewhere else. I am wondering whether something else is going on since the login itself seems buggy (I can enter the password once, but then the phone does not give me a keyboard for a second try, so I need to reboot again).

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You have to ask with the opposite view: Could an attacker get access to your daughters data by simply having her phone after you enabled debugging options? In a perfect world of course not. And USB debugging still requires to confirm access and adb still runs in the user context, not root context, so I doubt there is a "legit" way to enter your daughters phone.

Using a vulnerability

This is probably your only bet to get into the device without factory reset and since your daughters phone is a Pixel 1 that is out of software support, there is a good chance that it could work.

One such vulnerability was the Pixel Lock Screen Bypass. I'm not sure if the Pixel 1 is (still) affected by the vulnerability, though. So please give it a shot.

There is a video by Seytonic explaining the vulnerability in detail. The steps are:

  • Boot the Pixel and put in your SIM, so it asks for the SIM PIN
  • Please make sure that you have the PUK of your SIM card available to not lock yourself out of your carrier service
  • Enter a wrong SIM PIN purposefully 3 times, so it asks for a PUK
  • Enter the PUK of your SIM to unlock the SIM
  • The phone asks for a new SIM PIN, set it

Now the phone glitches and you pass the lock screen of Android. Once you are on the home screen you should be able to reset the password using the Family Link app on the parent device.

Final thoughts

Because of glitches like these, it is good to not use devices that are out of software support (at least when it comes to security patches). No matter the outcome, please invest in a new phone for your daughter, unless you want her at risk of data mis-use, online-impersonation or blackmailing when her device gets in the wrong hands.

In regards of losing passwords, I use KeePass to avoid losing memory of passwords (you can use it for card PINs, passwords, all sorts of stuff). On the plus-side, it allows you to generate unique hard-to-crack passwords that you will never forget. All you have to remember is your (hopefully long) master password to decrypt your vault.

I advice against using an online password manager. It's better to store an encrypted KeePass storage (which is just the kbdx file) in a cloud of your choice, a self-hosted cloud preferably.

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  • Thanks for the extensive answer. I was about to give up and reset the phone when my daughter tried one last time to log in and the phone just accepted her password. Weird. I think my main problem was why I would not be able to alternatively log in with my or her Google account instead. Would that be an additional security liability? Because an attacker would not have a significantly easier time to get into a stolen phone that way, right? Thanks for the SIM hack. I tried other glitches and they didn't work but I haven't seen this one. I'll accept your answer even though I couldn't test it.
    – Cerno
    Jan 17, 2023 at 6:52
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    Unfortunately if you log in with your own Google account password on someone else's phone, it will let you in as an additional account holder so you won't have access to your daughter's account. (You can set up multiple Google accounts on one android device - see Settings > Google and tap the > on the right of your account name so see what I mean.)
    – brit0n
    Jan 17, 2023 at 19:05
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    @Cerno I'm glad you get access back. If you are curious the same as I am: You can still test the SIM hack, despite knowing the passphrase already. I also doubt that you can't login into the phone using its PIN when you are problems with your Google account. The phone can dependent you to get into your Google account (2FA), but not vice versa. Jan 18, 2023 at 12:12

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