This chapter assume you use grub for your LFS. Issue the following to modify the file menu.lst:
cat > boot/grub/menu.lst << "EOF" timeout 10 color black/cyan yellow/cyan default 0 title LIVEKEY root (hd0,0) kernel /boot/lfskernel root=livekey ramdisk_size=16384 initrd /boot/initrd.gz EOF
Rename kernel, according to menu.lst:
mv -v boot/lfskernel-<version> boot/lfskernel
Where <version> is your kernel version
Now enter grub shell:
grub
Wile in grub shell, issue:
root (hdX,Y) setup (hdX)
Where hdX,Y represents your partition on the livekey
And quit grub shell:
quit
Now, you are done with your usb device. You can umount your key and now boot from it !