I have read the issue at https://developer.vuforia.com/forum/unity-extension-technical-discussion/gearvr-passthrough-camera-not-working-arvr-sample, and I get the same problem about this.
What I have done is very similer to freele:
OSX + Galaxy S6(SM-G9250) + GearVR, Unity 5.3.3f1 + Vuforia 5.5.9 + 'workaround'
OSX + Galaxy S6(SM-G9250) + GearVR, Unity 5.3.4p1 + Vuforia 5.5.9 + 'workaround'
I follow the steps in https://developer.vuforia.com/library/articles/Solution/Integrating-Gear-VR-and-the-AR-VR-Sample-in-Unity-5-3-and-above, and the built app could run on GearVR correctly, but when I saw the target picture, nothing happend. The app didn't layout the 3D model on the target picture. I don't know what is the problem.
Would somebody give me some helps? Thanks very much.