Needed: a grub2 expert

[Peter Tenenbaum <peter.g.tenenbaum@gmail.com>]

I'm having a problem with my debian squeeze desktop.  The problem is as follows:

I have a system with a software raid-1 root partition (set up with mdadm) and a non-raid boot partition.  The system uses grub2 as its bootloader.  Under ordinary circumstances everything works correctly, but when I have my (non-bootable) Seagate FreeAgent USB hard drive connected via the front-panel USB port, booting hangs.  Through use of echo statements, I've traced the problem to a block of code at the top of my grub.cfg file:

insmod raid
insmod mdraid
insmod part_msdos
insmod part_msdos
insmod ext2

The first statement executes correctly, but execution hangs between completion of the insmod raid statment and the insmod mdraid statement.

Since this is clearly a grub2 problem rather than a true debian problem, is there anyone who can point me to a resource on grub2 which might help me resolve this?  A grub2 guru would be wonderful, if any are known!

Thanks in advance,
-PT