We get questions like this all the time, and yes, Flygrip pretty much works with EVERY phone.
I am a firm believer of "Where there's will there's a way"
For curved back phones like the Nexus 6, or Moto X, or LG G-Flex, you can always make Flygrip work by adding a little extra adhesive to the bottom of the Flygrip. Sometimes adding a slice of adhesive to the bottom edges (not just in the center), to compensate for the curve. You may need to cut a section of the additional adhesive to do this, but shouldn't take longer than a minute to do correctly.
See picture below for a better understanding of what I am referring to since a picture is worth a thousand words in this scenario.
Or you can use our free cases and usually they provide enough compensation and flexibility that you do not need to add any additional adhesive.
Any questions, feel free to ask!