How to check the X820
Check X820 via Desktop computer (Recommend)
Please try formatting the hard drive if it still cannot be recognized.
Or run the following command to check it:
lsblk fdisk -l
Check X820 via Raspberrypi board
Please connect the Raspberry Pi and X820 motherboard correctly, you may refer to it here.
NOTE: Please use a good power supply, otherwise you may encounter some unpredictable problems!!Important!!!