Today's unfortunate discovery: efibootmgr is kind of bad
@mwhudson none of the words in its name made me think it was going to be something good
@glyph it's not bad in any very exciting way, it's just kind of deficient (there's no sensible way to see if the boot entry you want to ensure exists is already there, so the simplest thing to do is to create it anyway and see if there are now duplicates - but some firmware doesn't like repeated writes...)