In addition - it makes no sense to reboot in a few hours, if the UFED - is a mobile portable device and the dump of your owner’s phone will be extracted immediately during a police search of the apartment (in AFU State).
Cellebrite Premium doesn't have exploits which work with GrapheneOS with a patch level later than mid-2022. The purpose of the locked device auto-reboot feature is getting the device back to Before First Unlock state before they develop exploits for a current GrapheneOS and Pixel firmware release. It defends against future exploits.
The user of the phone that has with important data - must do all efforts to turn off the phone before his return to the police. With one button or gesture of the finger. Any options.
We provide strong defenses against exploitation combined with getting the device back to Before First Unlock state. Whether or not people manage to reboot to turn it off, GrapheneOS does a great job protecting their data.
https://discuss.grapheneos.org/d/20401-grapheneos-improvements-to-protection-against-data-extraction-since-2024 is a thread about recent improvements to the defenses.
https://discuss.grapheneos.org/d/20402-cellebrite-exploits-used-to-target-serbian-student-activist is a thread about a recent example where GrapheneOS blocks all the exploited vulnerabilities for locked devices. It prevents one from being exploited even unlocked and the other 2 would be much harder to exploit due to the generic memory exploitation protections.
P.S. Support for Pixel 8 and 9 (Physical Dump ( ADB(Rooted) ), File Dump (Android Backup, APK Downgrade), Logical (Apps Data, Phone book, Call logs, SMS etc) ) added to the UFED version 7.72 (release from 2024-10-31).
You're talking about an extraction tool requiring them to already have the PIN/password. We're talking about their exploit products for law enforcement which do not have the ability to exploit modern GrapheneOS in practice, only iOS and Android. We have access to Cellebrite Premium documentation from January 2025 and can obtain more recent documentation if we ask.