I just finished putting together my Omnibus F4 V2 flight controller. Connected up via beta flight and tried to flash the board up to 3.1.5. As soon as the erasing step started the buzzer started screaming and the flashing failed to complete. I have disconnected the USB and tried booting to DFU mode (boot button pressed when power connected) but the board just screams! I have desoldered the buzzer and the RAM to 5v link and disconnected all other connections and I still get the same thing. Is the board bricked? or can anyone suggest what I can do now.