I just finish to install Ubuntu 11:10 on a machine with FAKE Raid 1 (AMD) enabled.
The installation worked fine but after reboot the computer freeze at BUSYBOX or showing a purple screen (not always but very often).
I try various settings as boot option without success, but at the end I noticed that grub is configured to use UUID for identify root partition. I try to change this behavior and now the machine boot every time successful.
Change /etc/default/grub as above:
Then update Grub conf: