2d sprite flickering on iPhone 6 but not iPad

Hello,

I'm working on a 2d game for iOS. The sprites I use are imported with FilterMode: point and Format: truecolor, vSync is off in the quality settings. I'm putting the camera position in Update on rounded pixels and still on iPhone 6 I get a little flickering on the edges of the sprites. For example when the camera moves, some vertical lines switch between a width of 2px and 1px very fast. Putting the camera on rounded positions helped on my iPad 2 but not on my iPhone 6.

I use a script to set the camera size like this:

 int height = Mathf.RoundToInt(targetWidth / (float)Screen.width * Screen.height);
 GetComponent<Camera>().orthographicSize = height / pixelsToUnits;

And here is how I put the camera on rounded pixel positions (it follows the character):

 private void updateCam(){
         float newX = RoundToNearestPixel (transform.position.x, 100);
         float newY = RoundToNearestPixel (transform.position.y, 100);
         Camera.main.transform.position = new Vector3 (newX + 6, newY, -15);
     }
 
     public float RoundToNearestPixel(float unityUnits, float pixelToUnits)
     {
         float valueInPixels = unityUnits * pixelToUnits;
         valueInPixels = Mathf.Round(valueInPixels);
         float roundedUnityUnits = valueInPixels * (1 / pixelToUnits);
         return roundedUnityUnits;
     }

Any ideas why it's still flickering? I'm working with Unity 5.2, xCode 7.1 beta and iOS 9.

Thanks! Stefan