Is there any chance that someone moved the jumper inside your NUC from its Normal position (1-2) to its Lockdown position (2-3) as described in section 2.3 of the Technical product specification? Also I do not recall the exact amount of time but 5 minutes is not too much longer than the normal length of time for updating BIOS. Of course normally there is text displayed on screen showing old version and new version and the various specific sections of BIOS which are being updated (before it finishes and does shutdown for reboot). Sorry I don't recall the LED activity during flashing.
Thanks Dougho. I checked the jumper setting. It is set on 1-2. I had also left the system uninterrupted for over 30 mins! No LED activity or HDMI response.
When I was checking through the BIOS event log, I could see the last message as BIOS FLASH UPDATE FAILED (30) 1/1/2014 0: 0: 0.The time seems strange. And the BIOS time is set to the current time.
Is there a way i can download the full event log which BIOS is creating? I can find a log find using the file browser in the BIOS, however, not sure how to view of copy it to other locations/folders.
Thanks for your help.
Sorry, that's all the helpful ideas that I had. 30 minutes is indeed way more than enough time; I am not sure and length can vary but I think approximate typical length might be around four minutes. Someone else may have other ideas, for example to try first restoring all BIOS defaults using that option in the BIOS, or if problem might be related to monitor then see if you can try with different monitor and/or cabling (such as no AVR in between NUC and monitor), or double-check that your download is good (should be since you tried multiple files).