Refer: http://askubuntu.com/questions/47522/how-to-bypass-try-it-install-screen-when-booting-from-usb-live-session-wit
Release with updates installed:
http://old-releases.ubuntu.com/releases/
$sudo nano /cdrom/syslinux/syslinux.cfg
Replace:
# D-I config version 2.0
include menu.cfg
default vesamenu.c32
prompt 0
timeout 50
ui gfxboot bootlogo
with this for 32-bit:
default live
label live
say Booting an Ubuntu Live session...
kernel /casper/vmlinuz
append file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash noprompt --
with this for 64-bit:
default live
label live
say Booting an Ubuntu Live session...
kernel /casper/vmlinuz.efi
append file=/cdrom/preseed/ubuntu.seed boot=casper persistent initrd=/casper/initrd.lz quiet splash noprompt --