problems with software RAID on 2.6.3 and 2.6.4.

I recently installed a system using RAID 1 via the SuSE install procedure. On 2.4.21-193, everything's fine, but after compiling 2.6.3 (and then 2.6.4 to see if that'd fix it), it sees the md devices and attempts to activate them, but fails to mount the root FS. I was wondering what's changed in 2.6 to cause this, and if there's a workaround? (Can't give much more info cos it all scrolls off the screen too fast and once the kernel's paniced with "Failed to mount the root fs", I can't scroll back to see if there's a specific complaint.) Thanks.