When following our instructions on how to setup a fingerprint for use with Touch ID, instead of repressing the same finger down five times to get a more accurate scan, simply press a different finger down each time. Scan up to five different fingers and then repress each finger until the iPhone has obtained enough data. (This will likely be three scans per finger). Repeat the process when you get to the edge scans. (You'll likely need to press each finger down once).
In testing, this worked flawlessly for us. We had no problem scanning each of the fingers to unlock the iPhone.
We're not sure who discovered this trick but you can check out a video below of Note Suwanchote demonstrating how it works.
Of course, we recommend that you use the correct method for scanning in the finger you commonly use to unlock your device. However, you might want to use this technique for a few of your additional slots if you want to provide easy access to the device for friends or family.
Take a look below!
Note*: We tried this method with 6, 7, 8, 9 and 10 fingers. It only worked with up to 5 fingers.