https://x.com/runasand/status/2017659019251343763?s=20
The FBI was able to access Washington Post reporter Hannah Natanson's Signal messages because she used Signal on her work laptop. The laptop accepted Touch ID for authentication, meaning the agents were allowed to require her to unlock it.
Not really, because tools like Cellbrite are more limited with BFU, hence the manual informing LEO to keep (locked) devices charged, amd the countermeasures being iOS forcefully rebooting devices that have been locked for too long.
Quick-press Volume Up, then Quick-press Volume Down. Hold the side power button until the screen turns black (approx. 10 seconds). Immediately hold both the side button and the Volume Down button for 5 seconds. Release the side button but continue holding the Volume Down button for another 10 seconds. The screen will remain black. If the Apple logo appears, the side button was held too long, and the process must be repeated.