I bought my current T42 second hand. When I bought it, it had Xandros Linux installed along with GRUB and Windows XP. The Rescue & Recovery partition was still on the hard drive, and it would begin to boot, but it would stop with a fatal error. I have since replaced Xandros Linux with Mandriva Linux 2008.1. Windows XP is still on the hard drive.
I just stumbled across the solution this morning at ThinkWiki to get Rescue & Recovery to boot. The following needs to be in the /boot/grub/menu.lst
title IBM Rescue and Recovery
parttype (hd0,1) 0x0b
The MBR written by GRUB can be used to launch the Rescue and Recovery application. However, if you leave the type of the Rescue and Recovery partition to 0x12 (Compaq diagnostics), trying to boot this partition will result in an error message "c000021a, Fatal System Error". To avoid that, and to make sure the recovery partition is always of the right type, add a line to change the partition type to 0x0b (FAT32) to the Rescue and Recovery partition's entry in your /boot/grub/menu.lst. Also, as we will be hiding the Rescue and Recovery partition from Windows (see below), we need to unhide the partition here to make sure it will be visible and bootable. So, assuming your Rescue and Recovery partition is the second partition, the GRUB entry would look like this:http://www.thinkwiki.org/wiki/Rescue_and_Recovery
Note that there is some additional information in the ThinkWiki link above that should be read by anyone planning to add this change to their GRUB menu.lst file.