Check out the "Host Connectivity Guide for AIX".  This is available on eLab Advisor or on the EMC support site.  You need to take note of the 'pprootdev fix' command as well.  The version you're stating 5.3.0.5, that seems to be your PowerPath version level.  5.3 left general support at the end of December 2012, unless you've got an extended support contract.  Running a host grab on this host would also probably be a good idea, and reviewing it for other software that needs to be upgraded, i.e. ODM, Power Path, Solutions Enabler, AIX TL levels.  From what I recall though bosboot needs to be ran on the underlying /dev/hdisk devices not /dev/hdiskpower.
Hello,  I have an AIX system running 6100-06-07.  Is it possible to run bosboot -ad /dev/hdiskpower0?  I'm running EMC Symmetrix 5.3.0.5.  Or, does a new version of EMC Symmetrix allow you to run bosboot against a hdiskpower device?
bosboot against hdiskpower devices