Reset Root password in Solaris 10

{0} ok boot -F failsafe
Boot device: /pci@400/pci@1/pci@0/pci@4/scsi@0/disk@wx000cx00xxxxxfdx,0:a  File and args: -F failsafe
SunOS Release 5.10 Version Generic_147440-01 64-bit
Copyright (c) 1983, 2011, Oracle and/or its affiliates. All rights reserved.
Configuring devices.
Searching for installed OS instances…
ROOT/zfsroot was found on root.
Do you wish to have it mounted read-write on /a? [y,n,?] y
mounting root on /a

An out of sync boot archive was detected on root.
The boot archive is a cache of files used during boot and
should be kept in sync to ensure proper system operation.

Do you wish to automatically update this boot archive? [y,n,?] y
Updating boot archive on root.
The boot archive on root was updated successfully.

# cd /a
# cp etc/shadow etc/shadow.21dec2012
# vi etc/shadow
root::6445::::::
:wq!
# init 6