mksysb restore fails with error 0301-165 bosboot failed

mksysb restore fails with error 0301-165 bosboot failed.
When trying to restore mksysb, when multiple paths are configured to the devices used to restore the image, an error similar to the following may occur:

0301-165 bosboot: WARNING! bosboot failed - do not attempt to boot device.
BOS Install: Could not create boot image.
   ID#        OPTION
     1        Continue
     2        Perform System Maintenance and Then Continue
   Enter ID number:

Rootvg exists on a SAN disk with multiple paths configured and served by PowerPath. In such a case, multiple hdisks are created with the same PVID causing the bosboot command to fail.

List the devices supporting rootvg.
Find the pseudodevice holding these hdisks.
Release the devices from PowerPath.
Remove the hdisks (all but one).
Run the bosboot command against the remaining hdisk.
Run the bosboot against the ipldevice.
Exit

Select option 2 when mksysb restore fails:

0301-165 bosboot: WARNING! bosboot failed - do not attempt to boot device.
BOS Install: Could not create boot image.
   ID#        OPTION
     1        Continue
     2        Perform System Maintenance and Then Continue
   Enter ID number: 2

Check the rootvg disks:

# lspv |grep rootvg
hdisk0          00aabbccddeeffcc                    rootvg          active
hdisk2          00aabbccddeeffcc                    rootvg          active
hdisk4          00aabbccddeeffcc                    rootvg          active
hdisk6          00aabbccddeeffcc                    rootvg          active
hdisk8          00aabbccddeeffcc                    rootvg          active
hdisk10         00aabbccddeeffcc                    rootvg          active
hdisk12         00aabbccddeeffcc                    rootvg          active
hdisk14         00aabbccddeeffcc                    rootvg          active

Find the corresponding pseudo device using any hdisk device from this list :
# powermt display dev=hdisk0

Pseudo name=hdiskpower0
Symmetrix ID=000297000000
Logical device ID=0000013C
Device WWN=60000970000297000000533030313343
state=alive; policy=SymmOpt; queued-IOs=0
==============================================================================
--------------- Host ---------------   - Stor -  -- I/O Path --   -- Stats ---
###  HW Path               I/O Paths    Interf.  Mode     State   Q-IOs Errors
==============================================================================
   3 fscsi7                 hdisk0     FA  3d:04 active   alive      0      0
   3 fscsi7                 hdisk2     FA  1d:04 active   alive      0      0
   2 fscsi6                 hdisk4     FA  4d:04 active   alive      0      0
   2 fscsi6                 hdisk6     FA  6d:04 active   alive      0      0
   2 fscsi6                 hdisk8     FA  2d:08 active   alive      0      0
   1 fscsi5                 hdisk10    FA  3d:04 active   alive      0      0
   1 fscsi5                 hdisk12    FA  1d:04 active   alive      0      0
   0 fscsi4                 hdisk14    FA  4d:04 active   alive      0      0

Remove the pseudo device to release the hdisks

# powermt remove dev=hdiskpower0

Remove the duplicated rootvg disks:

# rmdev -dl hdisk0
# rmdev -dl hdisk2
# rmdev -dl hdisk4
# rmdev -dl hdisk6
# rmdev -dl hdisk8
# rmdev -dl hdisk10
# rmdev -dl hdisk12
# rmdev -dl hdisk14

One of the above rmdev commands fails as expected, and only one rootvg disk remains:

# lspv |grep rootvg
hdisk12         00aabbccddeeffcc                    rootvg          active

Perform the bosboot commands manually:

# bosboot -ad /dev/hdisk12
# bosboot -ad /dev/ipldevice

(you may have to create the ipldevice for the "bosboot -ad /dev/ipldevice" command to succeed. In our case, you would do this with "ln /dev/rhdisk12 /dev/ipldevice)

If the bosboot commands work, then type "exit"

# exit

The mksysb restore continues to complete.

If the bosboot commands fail, work with your Storage admin to reduce the number of paths of the rootvg disk to one before the mksysb restore.

This solution is derived from the public IBM solution https://www.ibm.com/support/pages/mksysb-restore-fails-error-0301-165-bosboot-failed