Newly Dislabeled Drive Won't boot

# uname -a
OSF1 mcgcrc1 V5.1 1885 alpha

Hello All,

I have a system disk that is failing. I managed to get a new one in and
labeled but the system still won't boot off of it. The two disks are
identical RZ1DDs and we're creating an advfs boot partition.

We tried  these commands:
disklabel -wr -t advfs dsk17a
 

Then we created a domain and fileset and vdump-vrestored the existing /
partition to the new one. At the >>> prompt we typed the scsi id of the new
drive as follows:

b dfa100


And we get an unable to boot error.

Any pointers?

Thanks, 
Steven