NFC TagWriter fails in programming NTAG 413 DNA

[stefano_dellava]

Hi, I'm having problems programming an NTAG 413 DNA using the Android app TagWriter.
Programming the UID mirror is working properly. Programming the UID plus the Counter works, but adding the SDM field does not work.

The problem seems to me caused by the wrong calculation of the offset where the app has to write the SDM field.

my set is as follows:

URL type: https://
URL: productid.info?uid=0000000000000000x000000x0000000000000000000000
UID offset: 26
Counter offset: 41
SDM MAC offset input: 47
SDM MAC offset: 7

The problem is that the app do not allow to change the SDM MAC offset value and 7 is clearly wrong.

Please help. Stefano

[Kan_Li]

Hi Stefano,

I am sorry, but are you using the latest TagWriter App? The version on my hands works fine and doesn't require input the offset data, just click to select the options. Please kindly clarify. and URL info should start with something like https://www.nxp.com .

Have a great day,
Kan

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[stefano_dellava · Accepted solution]

Hi Kan_Li, upgraded the app, now it works. Thank for the suggestion.