[mikeash]

Supposedly, and also supposedly the Secure Enclave doesn't defend against this, depending on who you ask and how they're speculating. I've yet to see anything authoritative on this from someone in a position to know for sure.

The good news is that if you have a good password, not just a simple numeric passcode, you should be safe against this sort of thing regardless, unless the authorities can coerce or trick you into revealing your password.