First time user here.  I got a Rock64 board and flashed Armbian_20.08.1_Rock64_focal_current_5.8.6_desktop.img using Etcher to an SD card.  When I try to boot, nothing happens.  If I examine the SD card on my Linux PC, there is only one partition on it and it appears to be a kernel image.  I assumed that the .img file would have the U-Boot partition as well.  Is there a different type of image file I should be using that would contain everything that I need to boot?  If not, how do I create such an image?

56 minutes ago, Irene said:

I got a Rock64 board and flashed Armbian_20.08.1_Rock64_focal_current_5.8.6_desktop.img using Etcher to an SD card.  When I try to boot, nothing happens.  If I examine the SD card on my Linux PC

Images has everything you need to boot them and most of the images are also tested. But in case of Rock64 ... there are a few quality issues hidden behind different hardware revisions.

Try legacy kernel 4.4.y images or go this path:

 

Thank you, Igor. I tried a 4.4.213 image and that worked.