May I suggest you not sit on the fence here. If you support making initial image changes based on the distribution, and I think you must, then do so fully and with gusto. Anyone who does this kind of modification will understand the tradeoff between working with some distribution vs. working with the latest sources, so the recommendation should be unnecessary, and it raises uncertainty around the quality and completeness of the distribution that I don't think you mean to imply.

Thanks for the pointer to the info on the post-1.4 Unicode bump-in-the-road, which I had missed because I hadn't read the Makefile all the way through and because it wasn't anywhere near the target I was interested in (initial.image).  I don't fully understand why I have to know anything about it or why you want to assume a Unicode-capable boot platform. I guess we have had to customize the static linker for various other hosting platforms (Lucid Common Lisp and Scheme->C being the ones I worked with most recently), so customizing differently for S48 1.4 and 1.5 is plausible, but the dependency seems unfortunate, and it is especially unfortunate that it fails in such an obscure way.

For now I am reverting to version 1.4, until the next time I need to open another >2G file.

And yes, I understand that overall the whole build and distribution process is in much better shape than when I last worked on it.

Jonathan