title: Launching into portrait-orientation from an iPhone 6 Plus home screen in landscape orientation results in wrong orientation
body: <p>The actual title for this question is longer than I can possibly fit:</p>
  
  <p>Launching an app whose root view controller only supports portrait-orientation but which otherwise supports landscape orientations on an iPhone 6 Plus while the home screen is in a landscape orientation results in a limbo state where the app's window is in a landscape orientation but the device is in a portrait orientation.</p>
  
  <p>In short, it looks like this:</p>
  
  <p><img src="https://i.stack.imgur.com/sQ1o7.jpg" width="160"></p>
  
  <p>When it is supposed to look like this:</p>
  
  <p><img src="https://i.stack.imgur.com/msCDu.jpg" width="160"></p>
  
  <p><strong>Steps to Reproduce:</strong></p>
  
  <ol>
  <li><p>iPhone 6 Plus running iOS 8.0.</p></li>
  <li><p>An app whose plist supports all-but-portrait-upside-down orientations.</p></li>
  <li><p>The root view controller of the app is a UITabBarController.</p></li>
  <li><p>Everything, the tab bar controller and all its descendent child view controllers return <code>UIInterfaceOrientationMaskPortrait</code> from <code>supportedInterfaceOrientations</code>.</p></li>
  <li><p>Start at iOS home screen.</p></li>
  <li><p>Rotate to landscape orientation (requires iPhone 6 Plus).</p></li>
  <li><p>Cold-launch the app.</p></li>
  <li><p>Result: broken interface orientations.</p></li>
  </ol>
  
  <p>I can't think of any other way to enforce a portrait orientation <em>except</em> to disable landscape altogether, which I can't do: our web browser modal view controllers need landscape.</p>
  
  <p>I even tried subclassing UITabBarController and overriding supportedInterfaceOrientations to return the portrait-only mask, but this (even with all the other steps above) did not fix the issue.</p>
  
  <hr>
  
  <p><a href="https://www.dropbox.com/sh/m4rfosexlwkv3h9/AAD7QsiCqG7UTyhF-TjELra6a?dl=0">Here's a link to a sample project showing the bug.</a></p>
  
  <hr>