Just to add another data point, it took me several tries to successfully install 2.0. I connected using the USB interface, got the "failed" message first time, went back to 1.9, re-upped to 2.0 and got a "completed" message ... but dead silence from the guitar. Unplugged, replugged, down to 1.9, tried again, "failed", unplugged, replugged, down to 1.9, back up to 2.0 ... that last time a success.