I flash the armbian Ubuntu 16.04.6 LTS into the box (2GB/16GB S905X X96 mini) internal emmc long time ago and it is still working without problem. Now I need to upgrade Ubuntu to a newer version (at least 18.04) in order to support some software which requires a newer version of Ubuntu.

My question is how can I do the upgrade? Any instruction how to do it in my scenario (armbian already running from internal emmc, not sdcard).

 

Thank you

Upgrades between ubuntu or debian versions have never been officially supported by armbian.  The recommended approach would be to reinstall the newer version.

Having said that, it should be possible to upgrade following the standard ubuntu upgrade instructions (google for examples of upgrading from ubuntu xenial to beaver).  There are a couple of armbian specific things to look out for:  1) make a backup and be prepared to restore the backup as you might find that you need to try this process more than once to get it right - unfortunately because you are installed on emmc that is much more difficult than if you were running from an sd card.  2) After you run the ubuntu upgrade, and before you do a generic apt update/upgrade and certainly before you reboot, you will need to look at the armbian specific files in /etc/apt/sources.list.d and manually edit those files to convert them from the old ubuntu distribution to the new.

I have done this process once or twice just as a proof of concept, but I generally find that after a couple of years, its better to do a clean install and start from there in my personal opinion.

Thanks a lot. The do-release-upgrade did not work.
If I want to have a clean install with newest supported Ubuntu, how should I proceed?

All the information you need should be in the two TV box FAQ posts:

https://forum.armbian.com/topic/16976-status-of-armbian-on-tv-boxes-please-read-first

https://forum.armbian.com/topic/17106-installation-instructions-for-tv-boxes-with-amlogic-cpus