Comment 17 for bug 2004661

That's the problem, HP ilo does not have a PoweringOn / PoweringOff state, it has 'Reset' instead.
And per my discovery, it seems set next boot works 100% of the time only if server is off as "Reset" can alternate between Reset and On and Off until server is finally fully On. Setting pxe boot while server is On is probably too late.

I believe implementation should wait for server to be off before doing the set boot once request.
Snippet of code I pasted above is not good as the infinite loop could get stuck in case of incorrect credentials or non-responsive server but ideally, that is what we need to do except have a sane amount of retries instead of infinite loop.