Start HSS USB mass storage mode using the user button
Press the reset and user button together to reset the board. Keep the user button pressed while releasing the reset button. Keep the user button pressed until an alternate pattern show on the LEDs. Release the user button. The board should now show up as a USB flash drive. Copy image to the board using dd or Balena Ethcher. Once transfer completes, press the use button once more. LED pattern will change and boot of the new image will start.