Disk mapping confusion with the device command

[Phillip Susi]

I have an unusual disk setup where the hard disk can not be accessed 
using the conventional /dev/hda device.  I have been trying to explain 
the proper mapping to grub, but it looks like it doesn't understand.

I tried to explain the mapping with these commands:

device (hd0,4) /dev/mapper/via_hfciifae5
device (hd0) /dev/mapper/via_hfciifae

As you can probably guess, the raw disk itself is accessed using the 
block device /dev/mapper/via_hfciifae and the first extended partition 
is accessed via /dev/mapper/via_hfciifae5.  This partition is formatted 
with ext2 and I mount under /boot.  The bios sees 
/dev/mapper/via_hfciifae as bios block device 0x80, so grub should have 
no trouble booting from it.

When I issue the root (hd0,4) command I get an error message stating 
that the partition table is corrupt.  When I enable debug messages and 
verbose mode, I see a debug message saying that it is reading from 
/dev/mapper/via_hfciifae5.  It looks like grub is looking for the MBR on 
the partition block device instead of the disk block device, and I think 
that is a bug.

Because I explained to grub with the device (hd0) command that it should 
open /dev/mapper/via_hfciifae, it should look there for the MBR, but it 
isn't.  Am I doing something wrong or is this a bug?

For reference I am running ubuntu breezy which appears to have the 
package "grub (0.95+cvs20040624-17ubuntu7)" installed.