iPhone Plus Home Screen Not Rotating? It’s Your Display Settings
One of the more interesting features that arrived with the larger screen iPhone Plus models is the ability to view the devices Home Screen, where app icons are shown, in a rotated sideways horizontal format. This places the Dock onto the side, and kind of resembles a tiny iPad. To rotate the iPhone Home Screen, you simply need to turn the iPhone into a horizontal position, and as long as Orientation Lock is not on, it will rotate. Usually.
Sometimes the Home Screen on iPhone Plus does not rotate while other app screens do rotate, however, but the reason for this is quite simple; it’s the iPhones Display Zoom settings.