Here is what you can do: Tell whats Model, F/W ? Do you have connected terminal to pcb or pcb with hdd? What you do between send Z and U ? Describe everything. Screenshot doesnt tell much. As I think you did nothing after Z and before U. Ok, STM3500320AS firmware MX15 problem BSY error, HDD not recognized. I have connected terminal to pcb (only). Between Z and U I have simply mounted PCB on HDD with power connected. someone can help me?