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Comment by bri3d | Hacker News Reader

Previous discussion of XNU/Secure Boot on Lightning video adapters (2013) : https://news.ycombinator.com/item?id=5307781 .

This thread has some new information and maybe people will start playing with these more eventually.

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For more context, check out this comment on the Panic Blog: https://panic.com/blog/the-lightning-digital-av-adapter-surp...

Don't drink the kool-aid. An adapter that destructively compresses the signal is an unexpected and unmitigated disaster, not some cool quirk of Lightning that makes "the host not care what is hanging off it".

The real reason this abomination exists is because as recently as 2018, Apple is selling products with a connector that has the equivalent bandwidth of USB 2, not even close to transporting a single 1080p video signal.

It’s destructive, and it probably also introduces a quite decent amount of latency.

Yes - this is really quite astonishing. I imagine any video professional would be horrified to learn that their CABLES were recompressing their video. There's never an acceptable reason for that it's really amazing I haven't heard about it before.

I wonder what they use for the demos at WWDC.

Makes you wonder if some rogue device/adapter/charger could deliver malware (sploit/trickery) to it before or after it's booted from the host.

Unlikely since the Apple adapter contains no software. The firmware is loaded by the host device when it's plugged in.

Doesn’t that mean that a rogue device that did contain software and ignored the incoming packet might actually be trusted by the host device when it shouldn’t be? The twitter thread did say the firmware payload contained no personalization (like encryption keys, perhaps).

> The twitter thread did say the firmware payload contained no personalization (like encryption keys, perhaps).

To be clear, this just means that the firmware isn't tied to a specific device via the normal ECID/nonce pair like a normal iOS update is.

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