If you have a OrangePi or a raspberry pi ,

there is high chance that the version of grafana package in the repositories of your distribution is outdated
in my case , i use armbian , the repo is from ubuntu xenial .

the version of Grafana in the xenial repo is antique (grafana 2.6.0) and the version is bugged if you use a Headless version of the os ,
the icon are not displayed when you are connected to the grafana interface. (because of a bug in phantomJS).

if you have already the 2.6.0 runing , remove it first

apt-get remove grafana

Then use this page to download a recent version of grafana compiled to run on a arm cpu

wget https://github.com/fg2it/grafana-on-raspberry/releases/download/v5.0.4/grafana_5.0.4_armhf.deb
then 
dpkg -i grafana_5.0.4_armhf.deb

if the grafana service is not auto starting at the system boot , you can launch that command :

systemctl enable grafana-server.service

you can check with netstat that your grafana service is running if your server is listening on the tcp port 3000

netstat -tcp -l

now start your browser and try to connect to http://ip-of-your-server:3000