We did extensive research on the subject, there is no mystery. iOS will <i>only</i> read MIFARE tags with NDEF formatted data.
If you write NDEF data to a formatted MIFARE card, it will be 'compatible' with iOS.<p>Otherwise, only the UID can be detected.
The real mystery is why Apple refuses to open the low-level read commands. (To read NDEF, or determine that the data is _not_ NDEF, you need to read the card.)
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.
In my experience, the notification you see at the end of article was used to advertise your brand/site.<p>The number of obnoxious people/guerilla ad companies that printed and programmed NFC tags and stuck them in random places was way too high. In some cases, they would replace the businesses QR code with the NFC tag. In some cases that NFC notification would pop up instead of the business’s menu. Quite annoying.<p>Then there was a case where the person stuck the raw tags _under the table_, so putting your phone down in random places would spam this notification on your screen.
Has anyone managed the opposite feat, i.e. made a piece of hardware that can recognise an iPhone over NFC? I'm trying to design control system that relies on you touching your phone to various hardware readers (with some kind of unchanging key/identity), but off-the-shelf MFRC522 etc don't seem to work, and the 'official' Apple way requires an NDA...