bsdlabel showing value zero on fsize, bsize and bps/cpg for all partitions

Hello,

on freebsd version 6 and 7 I was relaying on bsdlabel to get block size :

# bsdlabel /dev/mirror/gm4s1
# /dev/mirror/gm4s1:
8 partitions:
#        size   offset    fstype   [fsize bsize bps/cpg]
   a:  4194304        0    4.2BSD     2048 16384 28528
   b:  8388608  4194304      swap
   c: 293041602        0    unused        0     0         # "raw" part, don't edit
   d:  2097152 12582912    4.2BSD     2048 16384 28528
   e: 52428800 14680064    4.2BSD     2048 16384 28528
   f: 225932738 67108864    4.2BSD     2048 16384 28528

but on 8.1 and 8.2 I get zero values :

# bsdlabel /dev/mirror/gm6s1
# /dev/mirror/gm6s1:
8 partitions:
#        size   offset    fstype   [fsize bsize bps/cpg]
   a:  4194304        0    4.2BSD        0     0     0
   b: 17186816  4194304      swap
   c: 1953525105        0    unused        0     0         # "raw" part, don't edit
   d:  2097152 21381120    4.2BSD        0     0     0
   e: 83886080 23478272    4.2BSD        0     0     0
   f: 1846160753 107364352    4.2BSD        0     0     0

Has anyone seen this?
Is it some step I missed on install?
Is there another command to get block size?

Thanks for your help,
regards,
Sergi