Remove glossy from my game icon in GameCenter app

Question

How to do it?

UIPrerenderedIcon removes glossiness only for springboard icons.

Answer 1

Has your binary been uploaded and approved by Apple?

In my experience, until you upload your binary, iTunes Connect and Game Center don't know that you want gloss to be turned off. They get this info from your app plist after you upload it. After your game goes live, the glossiness should be gone (that's what happened for me, anyways).