I've just spun up a brand new vagrant installation using the instructions here https://docs.armbian.com/Developer-Guide_Using-Vagrant/

When I ran compile.sh inside the VM it installed a load of packages as it should, then eventually failed due to dialog not being installed.

 

A simple apt install dialog fixed everything, presumably the build system needs to be updated to install dialog as well?

"dialog" should be installed by scripts by default, but now looking at this, it probably failed due to missing/old package lists (which usually doesn't happen on fresh Ubuntu installations but may happen in a clean Vagrant box). So we need to do a small fix to update package lists when installing pre-dependencies.

I don't really know anything about vagrant at the moment, this is the first time that I've used it in anger so to speak, but that sounds plausible.

It was a trivial fix to get things working again, I just thought that I would flag it.

Same thing happened to me with a VirtualBox install of the mini.iso.   Picked the "Basic Ubuntu Server" and "SSH Server" Ubuntu install selections.

 

Then compile.sh complained about missing dialog command.   

 

Solved (from root) with "apt install dialog".

This has now been fixed: https://github.com/armbian/build/pull/1772