I've write the SD again with the image! I am now able to see fstab:
root@orangepipcplus:/mnt/etc# cat fstab
/dev/mmcblk2p1 / ext4 defaults,noatime,nodiratime,commit=600,errors=remount-ro 0 1
tmpfs /tmp tmpfs defaults,nosuid 0 0
/var/swap none swap sw 0 0