@User: For one, it means you shouldn't run ext2sim with "extresist on". Technically, it should work to re-write a .sim file annotated with the same extracted resistances, but since there isn't any tool that can make use of it, then it's not very useful. It's annoying, though, that you have to remember the state of "extresist on", especially as the same state is used for both "ext2spice" and "ext2sim", meaning that if you run the full "extresist" sequence of commands, you have to turn "extresist off" before starting again, or things will go badly wrong starting with "ext2sim" (the alternative is to remove the .res.ext files before restarting, or exiting magic before restarting).