I tried this link :
http://www.pendrivelinux.com/boot-mu...2-using-linux/
and formatted an usb stick from a Kubuntu 12.04 desktop ("try ubuntu" option).
Booting from this usb stick brings on a black screen (no grub menu).
Can you give more details to :
- create a bootable USB-stick
- install grub2 & configure it
?