A very very small request:
It might be nice if the firmware updater stores the most recently used paths for the Main and Aux firmware (separately) so that the load dialog went there first, instead of a default path. (I’m only on Windows, and haven’t reviewed the code, so I don’t know what it does on MacOS.)
For anyone doing firmware hacking that would save a few seconds of selecting the build directory each time (and the occasional uploading of the Aux firmware to the Main controller --thanks for including the MIDI short circuit trick, it works perfectly! )