@nicolasbulb I unfortunately don’t have an MPC to validate, but with the small collection of USB Midi devices I do have Norns: Fates, Arduinoboy, Organelle, and Mac running Ableton I’ve had no troubles. FWIW I’m waiting for 0-Coasts to be back in stock (they’re out of stock everywhere I’ve looked), once I have that I could test with what I have.
Building one is pretty easy, but if that’s tricky for you and you’re not in a rush I’m wrapping up a PCB design and hope to have the boards in hand by early July. Assuming there are no flaws or issues I would be willing to build you one for the cost of materials (e.g. 2 Pro Micros) and postage.