I recently purchased a used studiolive mixer from a friend of mine. All 16 channels were working perfectly, until I performed a software update to use Universal Control, where now only channels 1-4 will register any audio and function normally, rendering 5-16 completely useless, they will not register audio at all. I've taken apart the entire mixer, and there are no loose cables inside the unit. I'm decently sure that this is a software bug. How can I go about downgrading the unit? I've already downloaded and old version of UC, but it won't recognize the board.