在你的NavigationController里面加几句话：

- (void)viewDidLoad
{
[super viewDidLoad];
self.delegate = self;
}


- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
UIViewController *vc = [[UIViewController alloc] init];
[self presentViewController:vc animated:NO completion:NULL];
[vc dismissViewControllerAnimated:NO completion:NULL];
}

详情见http://stackoverflow.com/questions/15519486/presenting-navigation-controller-in-landscape-mode-is-not-working-ios-6-0

主要是，你一直是在push和pop，rootViewController始终NavigationController。不旋转设备，不会引起auto rotate动作，只能用一些其他奇葩的方法了。

你要用presentViewController，改变了rootViewController，就不会有这些问题了。