Confirmed that the problem went away with update. The keyboard was basically unusable before, getting stuck on other layers all the time. I’m very happy that now it seems good!
I tried updating through Chrysalis, but that ended up not working for me. I now suspect that the reason is that I was holding the “Esc” key, but really should have held the “bottom left key” instead (i.e. what is Esc on default layout). But before I figured that out I went through this howto:
… and that works as another way of flashing the FW (The keyboard is called “Atreus 2” and is confusingly stashed below “Technomancy” instead of “Keyboardio”.)