Different person here, but Apple has tried it multiple times in different ways.

They started in ios14, iOS 17 got new Secure Exclave path that (A18, M4).

Search for “Secure Indicator Light”.

Also searching for “Secure Exclave” will reveal some fun reads.

That’s cool, but on iPhones, there is no indicator LIGHT. Only part of the screen indicates it. And if they can trigger stuff on your phone, maybe a daemon that accidentally covers that part with black also appears, and you wouldn’t notice.

Nope, it interfaces directly with the display driver and overwrites anything from user land or the OS.

That's actually amazing, didn't know that. Do you have an article with some more info on it? Love to read about this stuff.

Here’s an article with further links:

https://9to5mac.com/2024/09/11/iphone-16-privacy-feature-m4-...

I couldn’t find a more technical article but this was when it was released.