Gentoo ISO Modifying

You will need the following packages to work with the images and burn them.

emerge -uDN cdrtools squashfs-tools 

Check the iso name:

wget http://ftp.iinet.net.au/linux/Gentoo/releases/amd64/current-iso/install-amd64-minimal-20100408.iso

mkdir /home/tmp
cd /home/tmp/
mkdir iso-original
mkdir iso-new
mkdir tmp
mount -o loop install-amd64-minimal-20100408.iso /home/tmp/iso-original
cp -av iso-original/* iso-new/
umount /home/tmp/iso-original
unsquashfs iso-new/image.squashfs
rm iso-new/image.squashfs

this is purely a example

mkdir -p squashfs-root/custom/host1
mkdir -p squashfs-root/custom/host2
cp /usr/local/backup/backup.20100304* squashfs-root/custom/host1/
cp /usr/local/backup/backup.20100313* squashfs-root/custom/host2/

mksquashfs squashfs-root/ iso-new/image.squashfs
cd iso-new
mkisofs -R -b isolinux/isolinux.bin -no-emul-boot -boot-load-size 4 -boot-info-table -iso-level 4 -hide-rr-moved -c isolinux/boot.cat -o /home/gentoo-custom.iso -x files ../iso-new/ 
cd /home 
rm -fr /home/tmp

1. Boot the iso
2. The custom directory can be found at /mnt/livecd/custom/