I'm interested to hear about this as well. I might be confabulating a bit, but just a bit, but I remember hearing Keller say that Zen is structured that way that there's nothing stopping them creating a different ISA frontend and say putting out an Arm processor instead of X64. That it actually wouldn't be much.
No, AMD’s Zen had a sister uArch that was ARM-based[1]. They were originally targeting it for servers, but ended up releasing only one or two fairly bog standard ARM cores before abandoning the venture.
