Thanks Jarret. Your procedure's image (ubuntu-18.04.2-preinstalled-server-arm64+raspi4+kvm.img) is downloaded from cloudkernels.net. Who at cloudkernels.net can I contact to ask if there is either a 16.04 img file or a procedure to build a 16.04 .img file?
Jarret, Please consider commenting on my bid to retrofit 16.04 on the rPi4 https://askubuntu.com/questions/1204703/16-04-retrofit-for-raspberry-pi-4 I would like to understand what understanding is required to develop the procedure above to retrofit 18.04. Thanks!