<i>I guess when the FBI compels them again</i><p>That&#x27;s a bit of a specious argument though – of course, if they produce different software in the future, it could be used again!<p>If the FBI want their own ability to sign Apple updates, then that&#x27;s obviously a different situation. But the point you were making – that it&#x27;s not possible to write software that will run on only one device – is not true in this case.<p><i>This is not mysterious. Can the FBI require a software company to subvert their own security guarantees? Should they? Do bank vaults have back doors for the FBI?</i><p>I don&#x27;t really know the right answer.