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Comment by BoppreH | Hacker News Reader

This is actually useful for smartphones. Sometimes smartphone malware is capable of infecting a device but not persisting, so reboots clean it back up.

At least if you trust the NSA's advice: https://s3.documentcloud.org/documents/21018353/nsa-mobile-d...

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On GrapheneOS, restarting also brings the device to a BFU state, which makes it loads harder for an adversary with physical access to unlock it.

yep, and this is the case for both major mobile operating systems

fun thing is that graphene had the feature to automatically reboot on a timer after inactivity for a while, but now ios also ships it :D

I remember something where on maybe mainstream Androids you'd have to fully turn off in order to turn it into BFU, but maybe it does just by restarting now.

Huh, interesting. I wanted to see how to enable this on iPhone, and the answer is that it’s built into iOS 18+ and will happen automatically after 3 days of no usage.

Yep, on GrapheneOS you can set it to a very short period (IIRC it is 10 minutes, don't have my phone here). Shorter timeframes than 3 days is useful in a lot of circumstances. I think in most scenarios where some agency uses Cellebrite or alike, they'll just make sure to do it immediately after confiscating a phone and not after three days.

It's another example of iOS security theater. It can be sold as "Apple cares about privacy", but it does not add that much meaningful security. (Just like: iMessage is end-to-end encrypted, but it doesn't really matter because most people don't enable ADP and only have iCloud Backups that are encrypted at rest.)

This isn't some magical GrapheneOS feature. iPhone and Android both do it as well.

You may be unfamiliar with its history. It was, for several years, a GrapheneOS feature. ("Magical" is up to the reader.) After much encouragement from the GOS team, Google, and separately Apple, implemented it years later.

GrapheneOS's implementation of it still remains the most robust. More info:

https://grapheneos.social/@GrapheneOS/113450215897626825

https://www.techtimes.com/articles/300621/20240115/grapheneo...

https://www.simplymac.com/ios/new-apple-security-feature-reb...

https://9to5google.com/2025/04/16/android-auto-restart-secur...

The same reason I barely restarted my iPhone for a few years. The `checkra1n` jailbreak had to be reinstalled each time (though it was easy):

https://checkra.in/

This is one of the features I appreciate with OneUI, I can set it to automatically restart it in the mornings.

The people that I know, in the security field, restart their phones, multiple times per day.

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