A little more info - it looks like the latest i386 package may have been incorrectly built? I might start playing around trying to build from ports on the soekris, but it may take a while :)
https://github.com/golang/go/issues/35789 I don't really understand why I'm still seeing the "xorps" instruction short of a) the port not being built with GO386=387 (based on that conversation) or b) there being a bug somewhere in Go (or c) PEBKAC).