Hi there!
Is Unity supporting gyroscope in Windows Phone 8?
Because it doesn’t work…
I tested my prototype on Lumia 820 & 920. On both gyro doesn’t work, but same project work perfectly on my BB Z10.
Any ideas? We need gyro on WP8 to our projects… 
Gyro on WP8 is turn off by default…
Input.gyro.enabled = true;
solved problem 