(floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p (Etherboot
from network adapter 1-4), hard disk boot is the default. To apply a
particular boot order only on the first startup, specify it via
-@option{once}.
+@option{once}. Note that the @option{order} or @option{once} parameter
+should not be used together with the @option{bootindex} property of
+devices, since the firmware implementations normally do not support both
+at the same time.
Interactive boot menus/prompts can be enabled via @option{menu=on} as far
as firmware/BIOS supports them. The default is non-interactive boot.