The problem here is that the serial wire cannot communicate with the part when it is in Hibernate/Shutdown modes. So overcome this situation, enter the serial downloader mode by pressing the BMODE switch (SW1 on the Ez-Kit) during reset. Now the part waits for the data over UART instead of executing the user code and thereby not entering the power-down modes.
Can you update with regards to this issue .
It will be very useful.
With best regards and wishes