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