Luckily it doesn't mess the Bifury up permanently... you just have to re-install the firmware and eject specifically from Windows for it to work again.
I had a physical PC, but I have a feeling that a VM should work as well. Failing that, you COULD try compiling mtools on a mac and using the instructions earlier in the thread from cscape, but you have to use this configure line to get it working on the mac:
./configure LIBS=-liconv
Yeah, I already tried compiling mtools on mac. Configure works with that flag, but, it still fails with make. I'll wait until someone can lend me a PC this weekend I guess!
No love on getting it to actually run on a mac though, even with unloading the USB modem drivers?