2.5.48-bk2 and -mm1 can't mount root?

Is this a known problem of some sort? I have tried 2.5.48-bk2 on one machine, and 2.5.48-mm1 on two.

The result is always the same:
disks and partitions are detected, but the root mount fails with a panic message that it couldn't mount root on major:minor.

The major:minor numbers are correct, a ide drive for the first machine and a scsi raid-1 device on the other.

Both machines runs 2.5.47 with no other problems than ALSA silence.

I use gcc 2.95.4 (debian) on both machines, and both uses devfs & preempt. One is UP and the other SMP

Helge Hafting