Bad news everyone...
Google screwed up the Android 7.1 update. An NFC-related bug blocks you when you want to use an unformatted (factory data) NFC chip.
For example, you've ordered new NFC tags, then it's impossible to write on it... that sucks.
This week, I've worked on a quick workaround for Android 7.1 users.
An update of NFC Tools has been published, with those following version numbers : 4.21.2 for NFC Tools and 3.21.2 for NFC Tools - Pro Edition
When you try to write something on your NFC chip and you get the the message "You have to format your NFC chip!", go to "other" tab then select "Format memory".
The workaround for Android 7.1 will fix the data and force Android to recognize correctly your NFC chip.
The fix works for this following chips :
- Ultralight C
- Topaz 512
I've already contacted Google about this problem, and a bug report is opened here :
But it seems like Google don't consider this issue as important...
If you see the problem on your device, I suggest to add a star on the bug report (top left of the web page).
Developers who have the same problem can also post a comment on the bug report.
This is a huge problem and I hope Google will reconsider the priority...
Also, feel free to send me additional feedbacks if the fix doesn't work on your device / NFC chips.