There is a mistake in OVI - file posted is fennec_12_443205.0_armel.deb There are errors when trying to install this file with dpkg. Just wait for this to be fixed.

PS. Now problem is fixed. Correct file in OVI. Try update now.

PS1 I still get errors when trying to update without deinstalling FF12. Something wrong with plugins. I don't want to uninstall FF12 until I am sure I can get plugins working in FF13, as I need certs imported via plugin so I can get my online banking working.