Thank you for joining the Intel communities.
In this case, the Intel® NUC Kit NUC5CPYH has been validated to work mostly with Windows but I don’t see the reason why it can’t work with Ubuntu, however, I strongly recommend trying to post your issue at the Ubuntu community to get some assistance in how to solve this issue.
Here are some links that can help you.
NOTE: These links are being offered for your convenience and should not be viewed as an endorsement by Intel of the content, products, or services offered there.
It looks like you have pointed me to a good trouble shooting guide. I shall follow that up.
Can I say I installed UBUNTU (took a couple of attempts, elsewhere on this forum you are advised to install 14.04.3 with the 15.04 Kernel, the earlier 14.04 versions will not work properly) and - apart from the lack of wi-fi - it works brilliantly. Display, sound all perfect. I use it as media player and I like to use the VLC media player as it does such a good job of getting film aspect ratios spot on and watched my first film last night with the NUC...love it.
I’m glad to hear that your unit is working great for you and I hope the links provided above can give all the help you need.