Iāve tried mg_128 in Awake, and got the top-left up-arrow button lit up - pushing it or the unlit down-arrow button next to it does nothing.
However, if I then swap out of Programmer mode on the Launchpad Mini Mk3 by going to something like Legacy mode (in which the lit 8x8 grid buttons work, but with the wrong positions), then switch back to Programmer mode, I get the arrow-down button in the top-left corner lit, and the other half of the 128 grid from Awake working. Pushing the lit arrow-down button (or any of the non-8x8 grid buttons) does nothing still.
A bit of swapping back and forth between Legacy modes eventually gets back to the left-hand side of the 128 grid on Awake, with the top-left up-arrow lit (and still unresponsive).
Throughout, I get orange lights flashing across the 8x8 Programmer mode grid ā as well as into the right-hand colum of > keys ā in positions which seem to reflect the Launchpadās MIDI note positions in response to Awake (this also happens in the Keys page of the Live mode, but in what I assume are correct note positions and not always in orange).
Update: using mg_128 and a freshly arrived second Launchpad Mini Mk3 works excellently well - some scripts (eg Timber Player) donāt seem to have keys light up, but they do function. Off to enjoy the wonderful Buoys script in all its glory. Huge thanks are due to everyone who made midigrid possible!