Error booting diag partition on T42 laptop

[G. Vincent Castellano]

I have an IBM T42 laptop which includes a diagnostics/restore partition and I
want to be able to boot this from Grub, as well as the XP and RedHat partitions.

I started out by booting from a RedHat install CD, deleted the Windows XP 
partition, and added  Linux Swap and ext2 filesystems, then I was able to use 
the diag/recovery partition to restore XP to the space remaining.  I can boot 
into XP and RedHat no problem, but not to the Diag partition.

Normally, you access the diag partition by pressing the blue 'Access IBM' button
while the BIOS startup is in progress.  This gets me a "Startup Interrupt Menu"
screen, offering me the ability to Resume Normal Startup;  Enter BIOS Setup
Utility;  or Choose Temporary Startup device.  Resume Normal gets me back to
Grub and neither of the others appear to afford access to the diag partition. 
Obviously grub has modified the MBR (or some other boot config data) in an 
unexpected manner.

My grub.conf looks like:

default=0
timeout=30
splashimage=(hd0,2)/boot/grub/splash.xpm.gz
# hiddenmenu
title Fedora Core (2.6.9-1.667)
        root (hd0,2)
        kernel /boot/vmlinuz-2.6.9-1.667 ro root=LABEL=/ rhgb quiet
        initrd /boot/initrd-2.6.9-1.667.img
title Diag
        rootnoverify (hd0,3)
        chainloader +1
title WinXP
        rootnoverify (hd0,0)
        chainloader +1

Partition table (from fdisk) is:

   Device Boot      Start         End      Blocks   Id  System
/dev/hda1   *           1        4651    35161528+   7  HPFS/NTFS
/dev/hda2            4652        4781      982800   82  Linux swap
/dev/hda3            4782        7113    17629920   83  Linux
/dev/hda4            7114        7752     4830840   12  Compaq diagnostics

When I boot from the Diag stanza, I get the IBM Rescue and Recovery progress 
bar, and then after a few seconds a bluescreen with:

STOP: c000021a {Fatal System Error}
The Session Manager initialization system process terminated unexpectedly with a 
status of 0xc000003a (0x00000000 0x00000000).
The system has been shut down.

The bit of research I did seems to show that the key technologies in the setup 
of the diag partition are (I swear I'm not making this up) BEER (Boot 
Engineering Extension Record) and PARTIES (Protected Area Runtime Interface 
Extension Services) but I don't have the context to pursue this any further. 
However I'd be glad to dig out any specific pieces of information from my T42 
that would help someone to move this forward.
--gvc