[coreboot] filo prompt, how to access usb disk?

[BeBa]

Hi,
I just flashed a ga-6bxc and find no way to access its usb sticks.
Filo has been compiled with IDE_NEW_DISK and USB_STACK. 
filo> kernel uda1:/vmlinuz 
spits out: File not found.

I think that the devices are not seen at all. Is there a way to find it
out?
probe seems to check only IDE stuff, is that true?
If so, then hwat else can I try?

thanks
BeBa