Firmware:

 

root@raspberry-pi:~# uname -a
Linux raspberry-pi 3.12.25+ #700 PREEMPT Thu Jul 24 17:51:46 BST 2014 armv6l GNU/Linux

root@raspberry-pi:~# aptitude install git

sudo wget https://raw.github.com/Hexxeh/rpi-update/master/rpi-update -O /usr/bin/rpi-update && sudo chmod +x /usr/bin/rpi-update

root@raspberry-pi:~# rpi-update

root@raspberry-pi:~# reboot && exit

root@raspberry-pi:~# uname -a
Linux raspberry-pi 3.18.13+ #785 PREEMPT Mon May 18 17:39:07 BST 2015 armv6l GNU/Linux