[pm]

This is cool, but the most interesting part is the part that requires investigation, i.e., what do the compatibility tools write to the card to make it iOS-compatible? I've done some work with iOS NFC, but not enough to have experienced the undocumented quirks.

[EricBetts]

My read of the proxmark code (https://github.com/RfidResearchGroup/proxmark3/blob/master/c...) is that the `ndefformat` formatted the tag MAD (https://www.nxp.com/docs/en/application-note/AN10787.pdf), which you'd do for NDEF, then had a single TLV TERMINATOR at the block where the NDEF message starts. Then he used NFC Tools to write on an NDEF text record (which iOS background reading would ignore) and maybe something else? After that he then used `ndefwrite` to write on a URL record. I wonder if he could have skipped the NFC Tools and written the URL record and gotten the same result. Proxmark dumps before and after using NFC Tools would be insightful.

[ewpratten]

Ya, I have no clue tbh.

This is one of those cases where I know I really should investigate further, but I'm taking this one step at a time. Perhaps digging in to the "why" will become a follow-up post

[pm]

I didn't intend for what I wrote to be a criticism; that's on me. I just found it funny the most interesting step was akin to "... and now you've drawn the animal", if you understand the reference.

[stavros]

But what happens if you dump the card with the Proxmark? Surely you should be able to see some differences.

Actually, I have all the components, so I'll try this now and report back.

[ChrisMarshallNY]

I suspect the comment (above, at the time I wrote this), where they mention that Apple only wants partners to be usable, is the Ockham's Razor answer.

Probably some "magic key" ID.

But this is not my area of expertise. It's a cool story, though, and why I like hanging here. Considering getting a Proxmark and the NFC Tools app, just to play around.