Linux Articles listed under "Xubuntu 9.04 USB Boot CD"
Create a USB Boot CD that can be used to boot Xubuntu 9.04 from USB flash drive on computers using a system BIOS that does not natively support booting from USB. The boot CD works by loading the initrd and vmlinuz kernel from the CD. Once the necessary USB drivers have been loaded, the boot CD proceeds to locate and load the filesystem from the USB flash drive. Because the USB driver modules are preloaded from the CD, the compressed filesystem can then be detected and loaded from the USB device even if your system BIOS does not support booting from USB.