I published one article for someone who may be interesting to install two different OS images into single eMMC. The aim of the article is to explain how to compose two OS images usually installed in eMMC and uSD which does not run with the same performance. Using this way both OS will run in the same performance as much as eMMC supports.
https://medium.com/@tobetter/installing ... pe=initial
Since there are limitations some OS is not able to be composed, what I've tested images are:
1) Ubuntu Mate 18.04 + CoreELEC
2) Debian Stretch + CoreELEC
3) Ubuntu Mate 18.04 + Armbian
4) Debian Stretch + Armbian
Instead of CoreELEC, I think EmuELEC would work since their build farm is the same. Also, please note that as some users reported Armbian needs some change of boot.ini
even you made to compose the dual-OS memory card, still you will need to change the same.
Also, since this the trial to publish a use case of Petitboot, please do compose at your own risk. Requesting and helping to me is still available.