I'm pretty sure that the LCIII ROM didn't boot my IIci, so this makes me question how much IIci stuff is retained into it. dougg3 may have tried this too, I don't recall for sure.

Is the cache card known to require ROM intervention? This is something like a PDS connection to the IIci cache I think, and I don't know if that's something that works "automatically" with the processor like a math co-processor. There are way too many variables and unknowns here to speculate about without just trying it. }

The cache may even be discovered and utilized by the OS itself.