Procedure to boot from the mirrored boot disk when system is not running:

 1. boot system to single user mode from cdrom:

    # boot cdrom -s

   or from network:

     # boot net -s

 2. mount the mirror device

    # mount /dev/dsk/c8t20000011C637232Cd0s0 /a

 3. Determine the TPD mirror path  

  # ls -l /mnt/dev/dsk/c8t20000011C637232Cd0s0
  lrwxrwxrwx 1 root other 47 Oct 21 09:33 /mnt/dev/dsk/c8t20000011C637232Cd0s2
   -> ../../devices/scsi_vhci/ssd@g20000011c637232c:a
  
4. Set the 'dmp_tpd_root_device' tunable in the vxdmp.conf to
    the mirror device path:

   # ksh
    # export TERM=vt100
   # vi /mnt/kernel/drv/vxdmp.conf
   
       #
      # comment out 'dmp_tpd_root_device' for boot device:
       #
      #   dmp_tpd_root_device="/scsi_vhci/ssd@g2000000087146f57:a";
      #
      # set 'dmp_tpd_root_device' to mirror device:
      dmp_tpd_root_device="/scsi_vhci//ssd@g20000011c637232c:a";

 5. boot the mirror 

   # umount /a
   # shutdown -g0 -i0 -y

   ok> boot <mirror_devalias>