First D5425WYK wouldn't take an OS install (multiple linux flavors: legacy and UEIF, stock and latest BIOS, multiple disk drives as well). I had continual IO errors - after dozen of hours it was clear the unit was faulty. I held out longer than usual because I have had good experiences with Intel ethernet adapters, and their motherboards have gotten good feedback for linux compatibility and quality. Why would it fail? Well the NUC seems to come from a different "branch" of Intel...
I RMA'd that one and tried a new unit. I got further but still have major issues.
Suspend is a key feature with the "NUC" idea that is anchored in energy efficiency. I wanted something quiet and the NUC good for sound as long as it isn't in serious use. Using a modern GUI the GPU fires up and the fan seems to oscillate between resting and sprint modes. At times it is QUITE loud. My wife is borderline hard of hearing and complained about having the unit near the kitchen.
So I turn on suspend so that at least the sound issues are only when the computer is in use. And that's where my seemingly good install goes off the rails. Suspend is 50/50 for booting back up. When it doesn't wake up it's 50/50 for responding to hard reboot. If hard boot doesn't work you have to disassemble the whole unit, which isn't so easy, and pull the CMOS battery. The CMOS battery harness in on the reverse side of the circuit board that is normally exposed from taking the case apart. Getting to the CMOS battery is a real trick - super fun for something that will seemingly be common on this unit.
Any how I pulled the CMOS battery and turned off "wake on LAN". Lots of people are facing bricks on these NUCs and that's one of the seeming fixes. Well I "non-booted" again after a failed suspend and after turning off WOL so I can only double fault the terrible BIOS on this unit. Intel is on the 33rd version and it doesn't work. So now I'm very frustrated. I just tried live chat but it was too busy - no one to field my chat.
Any how... I'm an MIT electrical engineer with a decade of linux under my belt and two decades of system building. I built a computer from scratch for a class in less time than I've spent on my multiple NUCs and that was literally wires and breadboard. My impression of Intel is torched with the poor BIOS implementation here. Intel - get on it or stop selling garbage.
Why won't your NUC's boot? I just don't get it. I understand suspend not working... that's been tricky for the Taiwanese MB manufacturers like ASUS and Gigabyte. I would expect Intel to get it right but to brick on suspend is a total failure.