Apple Lightning Connector Serial Access | Hacker News Reader

Apple Lightning Connector Serial Access

ramtin-amin.fr

162 pointsDaGardner15 comments

Basic details about the ID/authentication protocol have been known for a while: http://www.eevblog.com/forum/oshw/oshw-apple-lightning-conne...

It'd be interesting to see where this leads. I'm willing to bet that the Chinese have RE'd most of the protocol, but have kept the secrets to themselves. (If you're curious to learn a foreign language, and have some interest in electronics, learn Chinese - there is a lot of stuff on that side of the Internet that can't be found in English. The whole "Gongkai" ecosystem that bunnie writes about, for example: http://www.bunniestudios.com/blog/?p=4297)

That "BRICK_ID" signal sounds a little ominous...

Ten-years-ago me would have been shocked at the notion that cables now contain computers. I feel like I've just barely come to terms with the idea that computers are actually collections of computers, of which some are controlled by their owners.

your comment reminds me of this -

http://spritesmods.com/?art=hddhack&page=7

it makes you wonder how many Linux capable processors actually make up the computer you run..!

Searching https://www.google.com.au/search?q=iBoot+for+n53,+Copyright+... shows that this page could be the only place that the boot messages have been logged. Wonder if this will lead to new jailbreaks?

Not directly; iBoot outputs stuff to serial, but I don't think it accepts commands over it - or if it does, it would be the same locked-down interface you get over USB. (I should check which one.) However, serial over the old 30-pin connector has in the past assisted jailbreak-related software by making it easier to do low-level debugging.

Well, there is this line in the output:

    Delaying boot for 0 seconds. Hit enter to break into the command prompt...

...which gives at least the impression of there being a command prompt. As to how it would register a hit on that enter key remains to be seen, of course.

I wonder if "0 seconds" means it's disabled, which would make sense for a consumer build.

Interesting so first the device reads the lightning connector itself to configure the pins which is a plaintext exchange? Then the mfi handshake is done separately using a chip in the accessory? He didn't say exactly what had to be done to activate the debug UART. Presumably once he determined the ids for debug accessory there was no mfi handshake required or the mfi chips he had were able to pass the handshake. Surprising that the debug functions wouldn't be protected by a different mfi key.

Does the C in USB Type-C (USD 3.1) relate in any way to the the C in 'C10C'? I mean soon there's going to be a lightning pin at one end and a USB Type-C at the other end. I also guess engineers from both sides must already be talking to each other.

No. Due to the way that Apple designed the Lightning connector, it's not capable of higher USB specs than 2.0. Limited pins and the connector inside the socket only contacts one side at a time.

i'm always blown away when people reverse wire protocols like this - i don't even know where i'd start to do this sort of thing..

could this be used by apps on the device in any way?

Start by learning about logic analyzers: https://en.wikipedia.org/wiki/Logic_analyzer

You can get cheap (but slow) analyzers as open hardware, such as the Bus Pirate ( https://en.wikipedia.org/wiki/Bus_Pirate ). Also check out the Saleae USB analyzers ( https://www.saleae.com/ ).

Does anyone know the advantage of using two different pin outs on either side of the connector, instead of simply reversing one side?

As far as I know the differential lanes are swappable. They each have an identification channel assigned to them, so the combinations are (ACC0, Data1, Data2) and (ACC1, Data3, Data4). Keeping in mind that the function of each lane is found once it's plugged in the cable becomes fully reversible and routing inside the connector is simpler.

Well done, impressive willingness to deal with chip-scale BGA soldering and spend the time to reverse the wire format.

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