When updating an iPhone to a newer iOS version, you are required to enter your passcode (usually a PIN) before going ahead with the system update.
Before now, I had never wondered why. But after doing some research, the only source I have found is this Reddit post, in which the top answer states that the passcode is required to “decrypt the disk for the update.” I can see some truth in that, but then if this is the case, wouldn’t the key need to be stored somewhere other than the TPM for the duration of the update?
Is this the reason why, and if not, what is?
Or is the reason as mundane as because this is a privileged action, and a simple passcode isn’t a big deal? However, I don’t see how doing an unsolicited update could be dangerous.
