[giovannibajo1]

It used to be possible to do what you describe (cutting power at the right moment) and there were even physical bruteforce devices built to implement this but it's all been hardened in iOS 8 and there are no currently known ways to bruteforce a passcode. Obviously there might theoretically exist a software bug to do so, but there's no information around and it sounds even FBI couldn't find it if it exists

[akavel]

Could you elaborate on how's that prevented? I'm quite curious. [Or did someone already explain in some other post somewhere in this thread?]

edit: self-answer: the following post seems to have an answer: https://news.ycombinator.com/item?id=11115579, although it seems to describe a newer device than the one in the case; but I was interested in how such protection is possible at all, so that seems to answer it for me.