Index: wp-includes/vars.php
===================================================================
--- wp-includes/vars.php	(revision 20276)
+++ wp-includes/vars.php	(working copy)
@@ -71,11 +71,17 @@
 	} elseif ( strpos($_SERVER['HTTP_USER_AGENT'], 'Nav') !== false && strpos($_SERVER['HTTP_USER_AGENT'], 'Mozilla/4.') !== false ) {
 		$is_NS4 = true;
 	}
+	
+	// Set to true for mobile devices (smart phones, tablets, etc.)
+	if ( strpos($_SERVER['HTTP_USER_AGENT'], 'Mobile') !== false // most WebKit mobile builds (all iPhone, iPad, etc.)
+		|| strpos($_SERVER['HTTP_USER_AGENT'], 'Android') !== false
+		|| strpos($_SERVER['HTTP_USER_AGENT'], 'BlackBerry') !== false
+		|| strpos($_SERVER['HTTP_USER_AGENT'], 'Opera Mini') !== false )
+			$is_iphone = true;
 }
 
-if ( $is_safari && stripos($_SERVER['HTTP_USER_AGENT'], 'mobile') !== false )
-	$is_iphone = true;
 
+
 $is_IE = ( $is_macIE || $is_winIE );
 
 // Server detection