I got a used 75 from a guitar shop which they tested and it was fine. I tried to update it and it got stuck for a very long time, eventually I had to leave and take the phone I was updating it on with me. I came back to find a brick. It won't connect through Bluetooth (I eventually tried to update it via USB, but the amp isn't recognized) and it won't factory reset either. The ABCD lights flash when it's on and while it actually does give out a Bluetooth connection, it's not recognized in the app. It won't produce any sound at all, not even from the guitar. The seller said I could trade it in for another amp, but it's quite a long way and I want to have this one working. Does anyone know how to fix this?
