The requirement is that we have a tzupdater mechanism for updating, where the root filesystem is mounted on some alternate point for maintenance.

e.g.
# init 0
# boot net -s
# mount /dev/dsk/c0t0d0s0 /a

# /a/usr/j2se/bin/java -jar tzupdater131.jar -u
Backing up /a/usr/j2se/jre/lib/rt.jar to /a/usr/j2se/jre/lib/rt.jar.TZbackup
/a/usr/j2se/jre/bin/java not directly found in contents file, no package resolution performed.
(May not be in PKG form, not an absolute path, or is a symlink.)
Time zone data update is complete.
#

In this case, for tzupdater or tzupdater131, the mount point /a is nout found in the contents file, so no pkg fixup takes place.

chroot was attempted, but fails. A tzupdater example:

# chroot /a /usr/jdk/instances/jdk1.5.0/bin/java -jar /tmp/tzupdater.jar -u
(snip)
removef: ERROR: unable to open mount table </etc/mnttab>: Inappropriate ioctl for device
ERROR during removef SUNWj5rt ...
After the machine is up, pkgchk SUNWj5rt will show errors.

The update itself works as things stand, the Solaris pkg database update fails.