I have the same issue, I am trying to go back from 3.0.0.5 to 2.1.0.2 but the dialogue box expects a .led file rather than a .bin the 2.1.0.2 is. Renaming the file doesn't work and apparently the octave up+octave down combo doesn't factory reset it. I've contacted them about it two days ago however still not reply as I am sure you might have noticed from other people's comments, Arturia's support is not good.