I'm rathe late to the party, but this is what I found:
# armbian-config --help
Armbian config options:
Examples:
Install headers: /usr/sbin/armbian-config main=Sytem selection=Headers
Update, upgrade and reboot: /usr/sbin/armbian-config main=System selection=Firmware
Switch to nightly builds: /usr/sbin/armbian-config main=System selection=Nightly
Switch to stable builds: /usr/sbin/armbian-config main=System selection=Stable
Install default desktop: /usr/sbin/armbian-config main=System selection=Default
Change to ZSH: /usr/sbin/armbian-config main=System selection=ZSH
Change to BASH: /usr/sbin/armbian-config main=System selection=BASH
Change to stable repository [branch=dev]: /usr/sbin/armbian-config main=System selection=Stable
Change to nightly repository [branch=dev]: /usr/sbin/armbian-config main=System selection=Nightly
Install headers: /usr/sbin/armbian-config main=Software selection=Headers_install
Remove headers: /usr/sbin/armbian-config main=Software selection=Headers_remove
Install kernel source: /usr/sbin/armbian-config main=Software selection=Source_install
Remove kernel source: /usr/sbin/armbian-config main=Software selection=Source_remove
Install Avahi mDNS/DNS-SD daemon: /usr/sbin/armbian-config main=Software selection=Avahi
And then, according to the help:
# armbian-config main=System selection=Stable
Then, wait a long time and watch the show. I hope this helps...
