I figured this was a pretty good time to fix my crt0 to do data initialization and BSS clearing. So, the crt0 was updated correctly, the elf2cart utility looks like it's OK, but I found a problem with GAS. When a DATA directive is used with no data value, no space is actually allocated.

That's bad.

But also fixed.

So at this point, initial values for variables are used as expected, and the conversion utility works like a champ.