You mount the livecd-iso and extract the content and mount the squashed filesystem on it and the chroot in the system, change the stuff and then repack it again until you have a iso again that you might want to test as VM in vmware or anything similar before booting and relying on it.

Two documents explain the process on how to extract the whole iso to a chroot-able disktree. Its a bit confusing the first time, but you get used to it.

• http://www.debuntu.org/how-to-customize-your-ubuntu-live-cd
• https://help.ubuntu.com/community/LiveCDCustomization

edit /etc/casper.conf and be sure to rebuild the ramdisk

If you want to reboot without needing to press space after removing the cd-rom from the tray you do

rm -f /etc/rc*.d/*casper*

1. add your favorite background to /usr/share/backgrounds
2. gconftool-2 --direct --config-source xml:readwrite:/etc/gconf/gconf.xml.defaults --type string --set /desktop/gnome/background/picture_filename “/usr/share/backgrounds/MYBACKGROUND.PNG”

after changes that affect the ramdisk (like everything in /etc ...) you need to rebuild initrd inside the chroot-environment and then outside chroot need to move it to the casper-folder.

1. inside chroot : mkinitramfs -o /initrd.gz `uname -r`
2. outside chroot : mv NEW/custom/initrd.gz NEW/cd/casper/

the boot-screen is in isolinux/splash.pcx and can be changed there easily with gimp. just remember to convert to 255-colors indexed-format before saving again.

create a file isolinux/lang and put your prefered language-code in it. (de for german, fi for finnish ...)

create /etc/skel/Desktop and put your files there

/etc/skel/.config/autostart : you put every service there from /etc/xdg/autostart that you dont want to start and edit the file to change autostart from true to false.