So I've been working on a Nodejs tag writer for the NTAG424 DNA and I am still getting the hang of APDU commands. I am tracing the steps of the example from https://www.nxp.com/docs/en/application-note/AN12196.pdf but the documentation is confusing at times. I am attempting to write to file02 to take advantage of the SUN/CMAC mirroring of the tag by using Cmd.WriteData in CommMode.Full. When I write the data I get an <9100> OK response code but in CommMode.Full I believe I should be receiving an encrypted response with more data. Then when I attempt to do Cmd.ChangeFileSetting after WriteData in CommMode.Full, I receive a <911e> error. I have looked up and down for 2 days at my code to see if maybe I fumbled the Initialization Vector or encrypted data step, but I think those parts are all good. I am truly lost as to why this is happening. I am using the example provided on the documentation mentioned above, except I modified the header for CMD.write data to make the command length valid (I was getting <917e> before I changed it from <80> to <98>) since I believe the documentation has a typo for this step.

CMD for WriteData to NDEF: 90 8d 00 00 9f 02 00 00 00 98 00 00 {encData} + {macT} + {LE} CMD for ChangeFileSettings: 90 5f 00 00 19 02 {encData} + {macT} + {LE}

This is all in reference to 6.8.2 and 6.9 of the personalization example in the https://www.nxp.com/docs/en/application-note/AN12196.pdf document.