iOS 18.1 Features A New Inactivity Reboot Security Feature

iPhones aren’t secretly plotting together to reboot themselves, despite what some law enforcement folks initially thought. What’s really going on? Apple quietly slipped in a new security feature in iOS 18.1 called “Inactivity Reboot.”

First spotted by security researcher Jiska Classen on Mastodon, this feature forces iPhones to restart if they haven’t been unlocked for a certain stretch of time.

According to Corellium founder Chris Wade, that stretch is four days. So, if your iPhone is sitting idle for four days straight, it’ll automatically reboot.
This new setup is giving law enforcement a bit of a headache.

When an iPhone reboots, it enters what’s known as the Before First Unlock (BFU) state, making it much harder to crack open. Forensic teams prefer phones to be in the After First Unlock (AFU) state, where they’re more cooperative.

But this isn’t just about frustrating LEAs it’s also a win for everyday users. As cryptographer and Johns Hopkins professor Matthew Green points out, the real danger isn’t law enforcement; it’s thieves. This reboot feature means that if someone swipes your phone, they won’t have months to figure out how to break in. The automatic reboot ups your phone’s security game without really affecting your daily routine. Sounds like a solid trade-off, right?

Apple’s keeping quiet about this change, but if you’re curious, you can check out the iOS 18.1 code on GitHub.