&gt; if Apple produce a signed iOS version that allows the passcode retry limit to be bypassed on a single device, then in what meaningful sense does it operate on another device?<p>What prevents the iOS image from being loaded onto another device?<p>Apple isn&#x27;t magic; the code they write to verify device identity isn&#x27;t going to be the first perfect, unbuggy, unexploitable code written in human history. if(device_udid == terrorist_id) {...} might <i>seem</i> infallible, to you, but the reality is that the device_udid is just SHA1(Wifi MAC + Bluetooth MAC + ECID + Serial). All of those are writable, some via the Baseband and some via physical access. Generating SHA1 collisions is completely feasible for ~$1,000,000 of computing time, which is chump change to nation states.<p>There is no infallible way for Apple to make an iOS version for one single device.<p>Edit: And stories like <a href="http:&#x2F;&#x2F;abcnews.go.com&#x2F;Technology&#x2F;york-da-access-175-iphones-criminal-cases-due&#x2F;story?id=37029693" rel="nofollow">http:&#x2F;&#x2F;abcnews.go.com&#x2F;Technology&#x2F;york-da-access-175-iphones-...</a> make it absolutely clear that this is not stoping at a single device.