I have the same problem. After playing at home for a hour or maybe more the amplifier stopped playing and started with blinking the four tone leds. I turned the power of for a while but the four leds started blinking again when I turned the power on a bluetooth connection was stil available but the amplifier didnâ€™t work. A factory reset didnâ€™t work as well. I tried a firmware update and even a firmware downgrade with the Bluetooth connection and the usb cable but there was no difference. The strange thing was that an update with the 2.60 firmware resultated in a 2.51 firmware installation afterwards. It Sems that there is an internal software failure. I tried the factory reset and the update procedure with tone tab and master volume. Does anywone have an advise for me?