IBM i is an operating system. It runs on Power 6 and Power 7 hardware. I
think i5/OS was for Power 5. Anyway...
I'm not sure what you mean by FSB. I've heard of FSP, as in Flexible
Service Processor. The level of code your FSP is running is often
referred to as "firmware".
There are maps as to what level of firmware supports which levels of HMC
At one time I was so far behind I had to stagger upgrade. Upgrade HMC,
upgrade firmware, upgrade hmc, upgrade firmware... until current.
If you have an HMC do NOT allow PTF's for IBM i to upgrade your firmware.
Doing so can cause issues. In that case you could be religiously apply
IBM i ptf's and get your firmware so upgraded it's no longer supported by
your HMC. If you have an HMC it's better to let your firmware upgrades be
controlled solely by the HMC. There are ways to check and set that.
See "Supported code combinations" at
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