Well, there's always CHGIPLA and tell it to start the system in a
restricted state. Failing that, you could set that lpar to "Manual"
versus "Normal". Makes the upgrade process a little more "interesting",
but it's documented. And there's a stage during the manual mode where you
can tell it to start in restricted state.
There's also changing the system value QSTRUPPGM to some highly restricted
For the standard job scheduler we have a process that holds all entries
and records those it held, which were not already held. When we want them
to run a process releases those which were not already held is ran. Some
intelligence is built into that to say if the "Recovery action" was
*SBMRLS then submit the job right away.
You could probably duplicate this for the advanced job scheduler.