Update Raspberry Pi firmware and software

Check the kernel version with:
$ uname -a

And the GPU firmware with:
$ /opt/vc/bin/vcgencmd version

check kernel and GPU firmware version

To update the firmware can be done with rpi-update. Recent Raspbian releases comes with rpi-update installed.
$ sudo rpi-update

A reboot is needed to activate the new firmware

To update and upgrade latest software list, use the commands:
$ sudo apt-get update
$ sudo apt-get upgrade

updated

reference: http://elinux.org/R-Pi_Troubleshooting