I have the 52450 here, and yes.. it takes some work to get going. I will have to write up a detailed procedure, but, the gist of it is:
Basically, the 54250 NUC has new enough hardware, that the default kernel for precise will not handle it (missing drivers for both the Intel GMA5000 GPU, and the Intel e1000e ethernet adapter.), There is, however, a backport of saucy's kernel and xorg drivers which will remedy this.
Assuming the media director isn't configured (and if it is, you need to delete it)
* install linux-generic-lts-trusty kernel on core
* run /usr/pluto/bin/Diskless_BuildDefaultImage.sh to make the trusty kernel the new pxe boot default for unconfigured media directors
* alter /usr/pluto/bin/Diskless_CreateTBZ.sh, line 472, to be TARGET_KVER_LTS_HES="-lts-saucy"
* run Diskless_CreateTBZ.sh, get a few cups of coffee.
* boot the media director, it should do Diskless_Setup.sh
* reload router.
* let it build, and reboot.
* it should go into AV Wizard.
* Do the AV wizard, let it install everything.
At this point, ConfirmDependencies will try to install the standard packages for X... This is not what we want, so...
open a shell and go to the md, and apt-get install xserver-xorg-lts-saucy
At this point, reboot the md again.
You should then be able to go to the wizard > media directors, find the NUC, and then select vaapi under video acceleration, reload router.
At this point you should have full functionality with the NUC, including VA-API.
You can double check, with CPU usage, with blu-ray movies, you should not see CPU usage over 10%.
If you see more, or stuttering photo screen saver, make sure that the correct xorg is installed, and connect to Xine_Player's screen session to see if the correct driver is being loaded, or if an error results.