Police will find it harder to read a suspect’s iPhone without permission thanks to a security change. They’ll have to be much quicker to access the data on the phone.

The change means that the data connection in the Lightning port will be disabled after a set period if the phone is locked, a feature known as USB Restricted Mode.

When first included in iOS betas, the mode activated after a week. However, Apple’s now confirmed that in the finished version it takes effect one hour after the phone is locked. The port will continue passing power through to charge the phone, but the data connection itself will be blocked.

That’s a big problem for some of the techniques police use to brute force access to locked phones seized from suspects, which usually involves hooking the phone up to a computer or a dedicated cracking device. Depending on the type and length of the passcode, such methods often take many hours of processing, meaning they’ll now be unlikely to work.

The Register notes the change could have some unintended effects for people who use the iPhone as an unattended controller in medical and industrial settings.

The change follows a series of legal debates and challenges over the impact of both the fourth and fifth amendments when it comes to forcing a user to hand over a password or provide a fingerprint to unlock a phone.