can't boot fresh install of feisty 7.04 on old world mac

So - I'm frustrated. I have my trusty old beige g3 tower. Right now as I type, I'm running Edubuntu 7.04 from the live CD. I've managed to complete the graphical installation process as well to a SCSI drive, sda. My OS9 partition for BootX is /dev/sda6. Edubuntu 7.04 is installed on /dev/sda7. Swap is /dev/sda8. And just for kicks (and so the installer would complete its job, /dev/sda9 is formatted as "newworld" and evidently would be used to boot the system with yaboot on a newer Mac.
I've copied the ramdisk image and kernel files from the "boot" directory of the freshly installed Feisty on /dev/sda7, and pointed BootX at them.
When I try to boot it up though, it goes along swimmingly for 30 seconds or so, detecting devices, loading modules for all the hardware. And then it hangs for a couple of minutes before dropping me into Busybox with the initramfs prompt. From this shell I can easily mount the /dev/sda7 partition - I don't seem to be missing any modules. I just can't figure out what I am missing.

Is there some kernel argument I should be passing with BootX beyond "root=/dev/sda7"?

Has anyone gotten Feisty to boot up on a Beige G3 from a drive other than the live CD? If so, how?