Zen 7.x-5.1 does not utilise full width on iPhone 5

I've noticed Zen 7.x-5.1 does not utilise the full width of the iPhone 5.

To fix this I've amended the file: the file: templates/html.tpl.php

From:

<meta name="viewport" content="width=device-width">

to:

<meta name="viewport" content="width=device-width, initial-scale=1.0">

I also read that the Phone 5 doesn’t appear to like the width being set in the metatag. In which case the below may be a suitable alternative.

<meta name="viewport" content="user-scalable=0, initial-scale=1.0">