I've just got the m4 board and burned the latest image to boot m4, Rk3399-sd-friendlycore-bionic-4.4-arm64-20190610. However, I find an issue to automount my USB hard drive.

It can be mounted manually, but to automatically mount the device out of booting, I wanted to add the hard drive to /etc/fstab (which was empty by default, weired), and it couldn't automatically mount the device.

I should have edited fstab correctly.

Could anyone help me with the automount issue?