> mount -o loop /mnt/md0/sandbox /mnt/disk
> cp -ax / /mnt/disk
> umount /mnt/disk
> linux ubd0=/mnt/md0/sandbox
You can't just boot off a copy of your host filesystem. There are a few files
that you will need to fix up to use UML device names.
If you're new to UML, grab one of the filesystems off the UML site.
If you've been there and done that, then go back into your new filesystem
and make fstab use UML device names and make inittab use whatever tty names
That should fix up most of the problems.