BTT messing up modifier keys on Ultimate Hacking Keyboard

I'm using the Ultimate Hacking Keyboard (UHK). I installed BTT yesterday for the first time. After the installation none of the modifier keys worked as expected (Fn and Cmd were swapped and Option and Ctrl didn't work anymore). Only after uninstalling BTT was I able to get the UHK back to work normally.

Did I do anything wrong? Is there a way to get the two to co-exist?

BTT does nothing to your modifier keys by default. Unless you have configured some very special things in BTT I would think this was some coincidence.

Also BTT does absolutely nothing if it is not running, so quitting will always be enough - no need to uninstall.

Thanks Andreas. I re-installed BTT and this time paid more attention to when the problem starts.
When I record the first shortcut (Fn + 1), it records as (Cmd + 1) and from then on the Fn and Cmd keys are switched on the UHK (but continue to work as expected). The behaviour persists after quitting BTT. Unplugging/plugging the UHK restores normal behaviour.
Any idea why the recording of a shortcut would trigger the switching of two modifier keys?

I still don't think that's possible. BTT does not send any commands to the system that do persist after it is quit. All key remapping is done on the fly.

The only thing I could imagine is that there is some internal hardware function on UHK that swaps cmd and fn when pressing FN+1? (regardless of whether BTT is involved or not)

Ha - you are right! Fn + 1 does something to the keyboard layout even without BTT. I mean, what are the odds: using a key combination that messes with the keyboard layout as the first shortcut I'm recording with BTT? Now I have to figure out what and why it does that...
Thanks for your help with troubleshooting!

Haha yes, that's one of the weirder bug reports I have received :smiley:
It's unfortunate but quite a few keyboards use the FN key only for internal functionality and don't even really expose it to the system.