hi I have a few duos , two of them appear dead but when you monitor the debug serial port holding down the reset button at power up they display U-Boot SPL 2017.05 (Jul 10 2017 - 11:16:21) BOARD: Nanopi Duo id=4 DRAM: 0 MiB ### ERROR ### Please RESET the board ### simply question, how do i do that? ...