I've installed Aix 5.3 ML04 and attempted to run vmo to tune for oracle
It fails with "1485-122 Error writing in nextboot file"

I've trussed vmo and discovered that the cause is that tunchange calls
/usr/lib/perf/get_phase. This returns 0 signalling tunchange to abandon
the write.

The comment in tunchange implies that the phase is related to the
install of AIX and that the check is to counter the possibility of
perfstat not being "started". I feel quite happy that the install is
complete, what do I need to do to bump the phase up?

There aren't many postings on this subject, so maybe it's obvious!