as it has not been mentioned here, there is a method without the need for root posted on reddit:
Just received my Gear VR today and was looking for a solution to use Cardboard apps without rooting my phone.
Here it is:
- Install Package Disabler from the PlayStore
- Open it and check the box on the Gear VR Service
That's it. You can now plug your S6 into the Gear VR without Oculus Home starting up and use Cardboard apps.
To use Oculus Home again, just uncheck the Gear VR Service in Package Disabler.
The cool part is that the touchscreen and the back button is still working!
If you enable the "Developer Mode" in the Gear VR Service (before disabling it), you will also get the bonus of low persistence which makes the experience much better!
So have fun and all credits to enzo1982 @ reddit