More details to follow, but here are the cliff notes…

After moving WinXP disk to this platform, received the dreaded 0x7e stop on boot; google pointed me to a problem with intelpmp.dll, but this wasn’t my (initial) problem; I couldn’t even boot from the XP install disk which is not tailored for Intel.

Turned out a mobo bios flash (3.3 -> 3.5) did the trick (also had to remove the intelpmp.dll because the install came from an Intel box).

Hope this helps someone.

Will fill in the details later.