Booting off usb.

[Mike Power <dod.tsair@sbcglobal.net>]

I am having trouble getting my iBook G4 USB 2.0 to boot off a SanDisk 
Cruzer Micro 256 USB2.0 flash drive.  I have the flash drive partitioned 
with OSX's disk utility to have one partition on it with a HFS Standard 
filesystem on it.  On the filesystem I made a directory called boot.  
Put in the directory a vmlinux, yaboot, yaboot.conf, initrd, ofboot.b.

I use the following commands to display the location of the usb drive

dev usb0
ls
pwd

The commands display the following output
ok
ff9c7700: /disk@1
ok
/pci@f2000000/usb@1b,1 ok

I use the following command in open firmware to try and boot the device. 
boot usb0/disk@1:,\boot\yaboot
or
boot usb0/disk@1:2,\boot\yaboot
or
boot /pci@f2000000/usb/@1b,1/disk@1:,\boot\yaboot
or
boot /pci@f2000000/usb/@1b,1/disk@1:2,\boot\yaboot

After I execute the command I get a long pause, about 17 seconds, then I 
get the following error
can't OPEN: usb0/disk@1:,\boot\yaboot

Does anyone know what I am missing when it comes to booting off usb 
devices with an iBook?

Mike Power