Maker: Radxa

• If your RockPi-S is equipped with >=2GB SDNAND, you may flash an OS image directly to this internal flash as follows:
  • Build Linux x86 binary rkdeveloptool (sources) on host
  • Remove any SDcard
  • Hold down MASKROM button while you…
  • Power on or press the RESET button to enter flash mode
  • Release the MASKROM button after 2 seconds
    
    Next, run these host commands to flash the internal SDnand:
    • • sudo rkdeveloptool db rk3308_loader_uart0_m0_emmc_port_support_sd_20190717.bin
      • #await output: Downloading bootloader succeeded.
      • sudo rkdeveloptool wl 0 /path/to/uncompressed_armbian_image
      • #await output: Write LBA from file (100%)
      • sudo rkdeveloptool rd
      • #outputs: Reset Device OK.
        (check official step by step instructions)

     

• Holding the MASKROM button during reset prevents booting from internal the SDNAND.
• But, the board will always boot from the SD Card, if it finds a valid image there.
• Kernel serial console is on UART0.  [some older images have their console on UART2]
• The serial console operates at 1.5Mbaud with 8 data, 1 stop, and no parity bits.
  
• Black(left)=GND, White(center)=TxD, Green(right)=RxD

If you have a recent board (revision >=1.3), you should add the following line to your /boot/armbianEnv.txt file to tune for the newer “BS” silicon:

overlays=bs bs@1.3ghz

Refer to /boot/dtb/rockchip/overlay/README.rockchip-overlays for more information.