It's not the sensor. A security chain (any security chain) relies on the fact that each step of the chain is verified and trusted. Moving, removing, or replacin

It's not the sensor. A security chain (any security chain) relies on the fact that each step of the chain is verified and trusted. Moving, removing, or replacing any part of that chain requires that the whole chain is re-verified for trust. That'd be like me and you being in a secret club with a secret handshake. We've been meeting at the same bar every week for years. All of sudden, your twin brother shows up one day and, as always, I go to do our secret handshake and he can't do it. He looks like you. He comes from the same parents. I have no reason to suspect that it's not you because "you" showed up just like you do every week. But I know something's not right because he doesn't know the handshake. It's the same thing with an iPhone. That's exactly how you know that it's not third-parties that Apple cares about and that they're not trying to actively prevent anything done by third parties. If that's all it was, an OEM Apple sensor would be fine. It's not, though, because it has nothing to do with third-party vs. first-party and everything to do with security.