If you have a secure enclave within the device, then any hardware which has a direct connection to that secure enclave must be authenticated. It doesn&#x27;t matter about aftermarket replacements.<p>The entire purpose of the secure enclave is defeated if it trusts any hardware connected to it.<p>I&#x27;m not saying they didn&#x27;t test what happens when it fails. I&#x27;m saying they didn&#x27;t do <i>user testing</i> on what happens when it fails. I&#x27;m sure the engineers tried out the hardware authentication system. They just didn&#x27;t test the whole scenario once iOS was sitting on the end product.<p>So yes, it was put in place to stop any hardware that could not be trusted from accessing users&#x27; secure data. But no, it was not done to prevent aftermarket replacements.<p>The only reason I can see Apple caring about aftermarket replacements is because they are often low quality, and cause customers to go back to Apple with unauthorised repairs. (I&#x27;ve witnessed this more than once in an Apple store, someone coming in who had their screen replaced outside Apple and the touch digitiser was failing. Apple just sends them away.)