Hi everyone,
I'm working on a library application that uses ISO15693 NFC tags embedded in books to track checkout status. These tags are password-protected and require secure access in order to write the AFI (Application Family Identifier) field, which we use to mark books as checked out.
According to the tag spec (ST SL2S2602), the flow for writing to a protected AFI requires:
Sending Get Random Number (custom command 0xB2)
Sending Present Password (custom command 0xB3)
Writing AFI using Write AFI (0x27)
We’re using Core NFC's customCommand(requestFlags:customCommandCode:customRequestParameters:) on NFCISO15693Tag. While basic tag operations like getSystemInfo() and readSingleBlock() work fine, any customCommand immediately fails with this error:
Error Domain=NFCError Code=100 "Tag connection lost"
This only happens on tags that return ICRef = 0x01 in the system info response. The exact same tags and command sequence work fine on Android (transceive) and in desktop NFC tools. It looks like iOS is silently rejecting custom commands on these older tags.
Has anyone found a workaround for this? Or is this a known Core NFC limitation?
Would love to hear:
If customCommand works for you with tags reporting ICRef = 0x01
If Apple has documented ICRef restrictions for customCommand
If there’s a list of supported tag ICRefs or recommended replacements (e.g., ICRef ≥ 0x11?)
We’re happy to switch to a supported tag type if necessary — but we’d prefer an official answer or guidance before reconfiguring our whole tag supply chain.
Thanks in advance for any help!
