I had the same problem on my SGI 750. About 1/3 of the time it would boot fine, 1/3 of the time it would freeze up. The fix wound up being to install linux-image-2.6.25-2-itanium from lenny, which I've booted twenty times in a row without any problems - more info here: http://lists.debian.org/debian-ia64/2008/08/msg00000.html
Hope that's useful to someone. -- Brian Szymanski -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]