OS X Yosemite, 10.10.3, MacBook Pro mid-2012.

I am building a keyboard, and have mapped onto it all F1-F24 keys using tmk's firmware. F1-F19 all respond (I'm using Karabiner's EventViewer utility to detect keypresses), but F20-F24 do not. I know the keys work physically, but OS X doesn't recognize them.

Is it even possible to use F20-F24 on OS X, or are there other keys unused by OS X that will work (I want to use them as macro keys)?

  • 1
    Hi ZuluDeltaNiner. Did you find out more about this? Just curious, what keyboard design are you using?
    – grettke
    Apr 23, 2016 at 13:57

1 Answer 1


Here is the guessing answer, but makes sense, so probably possibly true.

What's peculiar about F21-F24 keys on MacOS?

  • “Makes sense so probably true” is faulty reasoning. This is like saying it makes sense that gas can go bad so it must be true that because my car isn’t starting, it’s due to bad gas.
    – Allan
    Aug 14, 2020 at 12:33
  • @Allan You are right, you shouldn't say it must be.
    – nichijou
    Aug 14, 2020 at 13:20
  • Or even probably true. Each is mutually exclusive. A supposition that makes sense and could even be true, doesn’t automatically achieve causation. There’s a possibility of being true, but not probably true.
    – Allan
    Aug 14, 2020 at 13:29
  • @Allan no, not.
    – nichijou
    Aug 14, 2020 at 13:31

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