Hi all,
by the way, I have generated for Ubuntu Desktop 16 and currently trying 18, it seems that section 3.1 could be complemented with information;
For Ubuntu 16.04 and 18.04
apply "Essential Yocto Project host packages",
then "i.MX layers host packages for a Ubuntu 14.04",
and finally invoke "sudo apt-get install curl"
For Ubuntu 18.04:
invoke also "sudo apt-get install python"
Hope it helps
Laurent