This message was posted on behalf of Intel Corporation
Thanks for your interest in the Intel® Joule™ Platform.
Personally, I don't have too much experience using Ubuntu with the Intel® Joule™. Nevertheless, I found these discussions that might help you figure out why once you boot it ends up on an initramfs console:
I would encourage to ask on Community | Ubuntu developer portal , since they are the developers of this image. They might be able to provide further assistance.
Have a nice day!