Original prusament tag and "copied" tag via prusa app result in different contents on the tag

[paul999]

First of all, I am not sure where to report it, as I think it might be a issue with the prusa app, but not 100% sure.

It looks like the prusa write the tag a bit different as when done in the factory. I have an original spool with tag, and with that I can see in NFC tools on iOS 2 records, one with a URL to the filament information, one with the application/vnd.openprinttag record.
When I write, via QR code from that spool, to a new tag, I don't see any of these records, it looks like the tag is empty.

When using a flipper zero, I am able to read both tags. With the original tag, I can see again the two records clearly available, including the URL to the tag, and after that the raw data of the application/vnd.openprinttag record.
The other tag, the flipper zero is again able to read it, but is not able to determine the records on the tag.

I have attached a dump of the two tags, and actual memory of the two tags is different.
What I expected was to see at least in both cases the records in the NFC tools/flipper one, instead of the it seems garbled data. The prusa app itself seems to be able to read the new created tag correctly.

original_prusament.nfc.txt
written_by_prusa_app.nfc.txt

[CZDanol]

Hello, this is how you can inspect the data yourself:

1. Take the Data Content hex data from your files to a separate file
2. Run them through the rec_info.py on this repo: cat hex_data.txt | python3 utils/rec_info.py --unhex --show-all

From that, you will get these two results:

orig.out.txt

from_app.out.txt

The script was able to read both of them, so they both seem valid. So I am not sure what the issue is.

There are some binary differences of how our app writes the chip compared to our spooling machines (the app uses more optimal TLV settings, the last four bytes of the SLIX2 chip are a bit tricky because they work different), but I don't see anything that should make the app-written tag to not work with NFC tools or flipper.

I also tried cloning a NFC tag through the Prusa app (albeit on Android) and read it back through the NFC tools, and all seems fine.

I have notified our Prusa app team to have a look on this though.