Counterfeit NTAG21x ICs in retail NFC tags?

[SudoSC]

I bought a wide variety of NTAG21x-based NFC tags from Amazon. They all work as expected, including the counter mirror feature. However, when I read those tags by the NXP TagInfo app, they all show "Clone tag" in the "IC Manufacturer" field and "Signature could not be verified with NXP public key" in the "Originality check" field.

Are NFC chips in those tags counterfeit or, perhaps, unlicensed? Is it possible that the tag vendors overwrote the ICs with their signatures and thus cannot be authenticated by the NXP public key?

Any suggestions or feedback will be appreciated! Thanks!

[Fabian_R · Accepted solution]

Hello,

Unfortunately, we provide no support for these products since as you mention they may be counterfeit. Our recommendation is to not rely on them for secure usage since the IC may be vulnerable.

We highly recommend to please contact any of our Partners for reliable products.