To Remove the Joomla Copyright Info. that is displayed in "Mobile Joomla" at the Footer,
For Joomla 2.5.x
Locate to, Your-Joomla-Root-Folder/libraries/cms/version/version.php
Line No. 50
Edit, public $URL = '<a href="http://www.joomla.org">Joomla!</a> is Free Software released under the GNU General Public License.';
Replace it with, public $URL = '';