I have been struggling with some signature problem for a GearVR app developed with Unity. I have one OSIG file for a specific device and the build is working fine on this device. I signed the APK with a keystore and uploaded it on the Alpha release channel of Occulus and it works fine on the device linked with the OSIG file.
The problem is, I get the "APK not signed" error on any other device trying to run the application from the store. Do you still need one OSIG file per device when the app is pushed on a release channel of Occulus ? (And if so, at which point does the app work on any device ?)
