To install the new i386 boot blocks (FreeBSD-current):

If you've done an ELF upgrade, your sources are up to date,
and you've done a recent "make world", all that should be
needed to install or upgrade the boot blocks is the command:

    disklabel -B $SLICE

If you haven't done a recent "make world", the following
may be necessary:

    # Ensure that /boot exists
    mkdir -p /boot

    # Install latest bootblocks in /boot
    cd /sys/boot
    make all install

    # Upgrade bootblocks for each target slice
    disklabel -B -b /boot/boot1 -s /boot/boot2 $SLICE

NOTES:

    o  You probably want to delete /boot.config after upgrading,
       though having one or more of the serial options -h -D -P
       in /boot.config may still be useful.

    o  For recent versions of disklabel(8), the -b and -s options
       can be omitted (RTFM/UTSL to check defaults).

    o  If you have only one FreeBSD slice per drive, you can
       specify the drive (eg. da1) rather than the slice (eg. da1s1)
       in the disklabel command.


Robert Nordier
<rnordier@FreeBSD.org>