Some time ago I replaced my original home server with a new one based on an Intel J1900 processor on an ASROCK Q1900 motherboard. This has slightly reduced the power consumption of my home server (which runs 24×7) but more importantly, massively boosted it’s performance. However, it’s left me with one minor problem – the system always hangs on reboot, preventing me from remotely managing the system.
I finally got around to looking at it this evening, and this post provided a wealth of information on how to go about resolving the issue. In my case, the default reboot method (using the keyboard controller) wasn’t working. Switching to the ACPI method immediately resolved the problem for me, on Ubuntu 14.04.1 LTS.
To implement the fix, open a terminal, and edit the file /etc/default/grub, making the line:
GRUB_CMDLINE_LINUX=""
read
GRUB_CMDLINE_LINUX=”reboot=acpi”
Then (again in the terminal) run the command sudo update-grub.
Since the setting takes effect the next time the OS starts, you’ll probably need to restart the server manually one more time before being able to remotely reboot the machine successfully.
Richard's Blog 
Hi Richard
Thank you for pointing that, got the same issue on a
Intel DH87RL Board,
Core i5-4570,
Ubuntu 14.04.1 LTS,
First time that shutdown -r now worked.
Thx rain
Thanks, didn’t think I’d find the fix so fast.
Just a slight warning … I’ve noticed that sometimes my motherboard *still* doesn’t reboot correctly. It’s less frequent, so it’s less obvious, and I don’t reboot my server very often, but there is clearly a problem still lurking in the reboot code somewhere.