The Images for the Single Board Computers are larger than the size an average 8GB Sd-Carde. I tried it with BananaPi, CubieTruck and Odroid HCx. To write the Images I used Etcher as well as dd.
Here the listing of fdisk after write it to a 8G SD_Card
And here the output of fdisk on a 16GB SD-Card:
It was possible for me to resize the second partition on a 8GB SD-Card and grow the file system to max (7.2GB)
So I like to ask to build the Images al little bit smaller so that they fit to an 8GB SD-Card.