The iPhone 12 camera, when transferred to another iPhone 12, appears to work on launch, but fails miserably in actual use. It refuses to switch to the ultrawide camera, responds only to certain camera modes, and occasionally hangs and becomes completely unresponsive.
There is zero doubt in my mind that this is completely deliberate, and doing some deep reverse-engineering would likely yield how it is done (if anyone does decide to investigate it, that is an article I would love to read about.) It's like the copy protection schemes in games that appear to be defeated easily, but have more hidden traps later on.
The wankers at Apple who implement this sort of thing should be ashamed of themselves. I hope the Chinese cracks this, as they are apt to do for the third-party repair industry, just to show that it can still be done.