I had the reverse issue. I had an app that I had originally set up to be portrait only. When I added landscape in Deployment Info screen, landscape worked on iPhone but not on iPad. I had to edit the Info.plist file to add the other orientations. Then it worked.
I had the reverse issue. I had an app that I had originally set up to be portrait only. When I added landscape in Deployment Info screen, landscape worked on iPhone but not on iPad. I had to edit the Info.plist file to add the other orientations. Then it worked.