thanks for the answers Andreas & Ruud. My memory of just how much RAM the original AmigaOS could address is a bit fuzzy, though I was pretty sure it was over 1gb and thought it might be 2gb.

I did not know for sure that increasing that original limit in MorphOS would break all compatibility with legacy Amiga software, so that is also an interesting bit of info.

I wonder if MorphOS will survive long enough to evolve past the original Amiga limitations, like the MacOS has, but still be able to run some of the older software, perhaps only via a version of UAE in the distant future.