Full screen web app in iPhone 5 (save to home screen)

gistfile1.phtml

<!-- standard viewport tag to set the viewport to the device's width
	, Android 2.3 devices need this so 100% width works properly and
	doesn't allow children to blow up the viewport width-->
<meta name="viewport" id="vp" content="initial-scale=1.0,user-scalable=no,maximum-scale=1,width=device-width" />
<!-- width=device-width causes the iPhone 5 to letterbox the app, so
	we want to exclude it for iPhone 5 to allow full screen apps -->
<meta name="viewport" id="vp" content="initial-scale=1.0,user-scalable=no,maximum-scale=1" media="(device-height: 568px)" />
<!-- provide the splash screens for iPhone 5 and previous -->
<link href="assets/splashs/splash_1096.png" rel="apple-touch-startup-image" media="(device-height: 568px)">
<link href="assets/splashs/splash_iphone_2x.png" rel="apple-touch-startup-image" sizes="640x960" media="(device-height: 480px)">

It seems that something has changed. The use of any viewport meta tag (even with content="") in a web app will cause the downloaded version to letterbox on an iPhone 5. Yet if you leave out the tag, navigate to the URL, download the app, it will open full screen, but of course the scaling is off. Now go back and place your meta tag into the document head and you get your app at full screen with the appropriate scaling.
Not very useful in the wild.

Not working.... Actually my deployment target is 4.1... Is it the problem with that? Please help.