I had the same problem with an FC3->FC4 CD upgrade. Nothing to do with grub: I am using lilo. Nothing to do with the order of kernel-mkinitrd upgrades IMHO: how would it work during installation. Anyway the problem goes on with kernel-2.6.12-1.1387_FC4 and kernel-2.6.12-1.1390_FC4. Happily enough I have a custom kernel with the scsi driver in.