We have a HP ML310 Gen8 V2 that had Server 2012 Essentials (not R2). We are trying to rebuild the server to Hyper-V core 2016.
Once 2016 core has been installed and we create the VM, mount the Server 2012 Essentials ISO we press any key to boot into the CD/DVD afterwards when we are presented with the Server installation screen (language/product key etc). the mouse works fine, however the keyboard doesn't.
We have tried enabling the guest services, reinstalled with Server 2012 R2 core instead of 2016 with the same issue. If we try another ISO such as Server 2016/Windows 10 on the VM it works perfectly fine. So I assumed it was the Server 2012 Essentials media, so we obtained some more with the same issues.