You need to use -O 2 to create a FFS2 filesystem, from
newfs(8):
Code:
-O filesystem-format
Select the filesystem format:
0 4.3BSD format file system. This option is primar-
ily used to build root file systems that can be
understood by older boot ROMs.
1 Fast File System (the default).
2 Enhanced Fast File System (FFS2).