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Comment by jupp0r | Hacker News Reader

Does anybody know how/why FaceTime/iMessage are coupled so tightly to the Wifi drivers? I'm assuming this is for communication with local iPhones for handoff purposes but I'm still surprised this requires special interaction with the hardware and doesn't gracefully fall back to just talking to the backend if driver features are unavailable.

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> doesn't gracefully fall back to just talking to the backend if driver features are unavailable.

Why should it? Apple only supports their own hardware so the software should never run into this problem.

Custom drivers trip some security features and "taint" the kernel.

How does that impact iMessage? Are parts of it implemented in the kernel?

I remember reading (perhaps here on HN) that Apple does weird/nonstandard things to wifi packets to enable Continuity/Handoff features, so it could be related.

I'm not a specialist, but there's a chain of trust you need to maintain to have the full set of features. If it's ever broken, you're sent to the gulag. I broke the chain when reinstalling like an old-timer on my M1 Macbook Air and was then forced to enter my password twice to unlock the Mac.

I had to reflash with a second Mac to restore the chain.

The application can see that the kernel is tainted and refuse to run. Similarly, some kernel-related functionality may be disabled. None of this requires iMessage to run in the kernel or have a module of its own.

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