Here is a convenient procedure to know for Solaris 8 and below. Usually after a / partition recovery, I use it to install a server's or workstation's boot block. For most people, the second argument is a little difficult to remember. Here is an example.
ok boot cdrom -s # /usr/sbin/installboot /usr/platform/`uname -i`/lib/fs/ufs/bootblk /dev/rdsk/c1t1d0s0