If my Android phone wasn't dead, I'd love to compare an iPhone's write against the Android NFC Tools app's write.
If anyone else has an iPhone, an Android phone, and a Proxmark, I'd be interested in seeing a three-way diff between them all.
EDIT: I'm going to try to cross-post to the DT forum to see if anyone has ideas.
Make a dump after doing "hf mf ndefformat".
Then make a dump after writing a payload from an iPhone. (since iPhone seems to want ndefformat anyways)
Then wipe again and make a dump after writing from Android.
Something's clearly up there. You can see that even IOS and Android disagree with each other on what NDEF should look like by a few bytes. Very interesting.
I used this page as reference when I was putting together the "magic bytes" in the final section of the blog post: https://www.oreilly.com/library/view/beginning-nfc/978144932...
Also, one thing that might be of interest: Even after a wipe and an ndefformat, my Android-written tag can be read by my iPhone 15.
NFC tools will only read it in compatibility mode, though.
Try wiping, then writing a URL from Android.
Then just tap to the iPhone and see if Safari opens or not. It shouldn't
I don't know if it's Vivaldi doing that, but I can't imagine they would have added NFC tag reading capability to the browser specifically.
Feel free to email me if you want, btw, as this thread is getting a bit too deep.
If you try to have another iPhone detect the badge, it appears not to work - unless you use NFCTools on that iPhone, too. I don't have conclusive proof but that's what the evidence seems to indicate.
Are you seeing something different?