Convert NRG to ISO:
$ dd bs=1k if=image.nrg of=image.iso skip=300
Change plymouth theme:
$ sudo update-alternatives –config default.plymouth
$ sudo update-initramfs -u
Update GDM background and theme:
$ gksu -u gdm dbus-launch gnome-appearance-properties
Install restricted format:
$ sudo apt-get install ubuntu-restricted-extras