I ran into a unique problem that I've not seen documented and which is perplexing enough to have made me register here and seek professional help.
To start with, I have two NUC8I7HNK boxes, one is marked HW ver.1 the other HW.ver3.
The one I'll refer to as HW1 seems to boot fine from anything I through at it. HW3 on the other hand chokes on USB boot. It boots fine from its internal SSD. The USB boot problem may not have always been an issue, but quite frankly after a while I put the sucker on a shelf and only recently started checking it out more thoroughly again.
Basically what happens when I insert a USB bootable device, whether it is a USB DVD/BD drive, or a USB stick and attempt to boot from it the box will refuse. In the case of the USB DVD drive I see that it actually reads the disk in the drive but then gives up.
Here is the possible cause which I don't know how to resolve:
If I hit F2 and check the listed available boot devices, the USB device is listed as follows:
UEFI : USB : HL-DT-STBD-RE WH16NS40 1.02 : PART 1 :OS
OK, so I know that the above is the make/model of the USB DVD drive (actually Blu-Ray drive), an LG external drive which I have in my garage and which I used a while back before switching to a smaller and much more portable Pioneer BD drive.
The kicker is the UEFI boot device line I quoted above appears every time I connect a USB bootable device, REGARDLESS of the make/model of the bootable device and regardless of whether it is actually a DVD/BD drive or a USB stick. So for example, I never see the Pioneer BD drive identified, or the Samsung USB stick, when I connect either, only that old LG drive, which of course is sitting in the garage, i.e. not connected to the NUC. Note: Secure boot has naturally been disabled, and USB boot is enabled.
This happens regardless of which of the six USB ports I attempt to use to boot from.
I suspect that each time I try USB boot the NUC will check the model number in the UEFI boot device info as above against what it detects and since they don't match it won't complete the USB boot.
The million dollar question is, how to fix this. I performed many of the 'usual' remedies: factory reset, BIOS upgrade, disconnect the CMOS battery, clear the security database, . I also compared the BIOS configuration virtually line by line between the HW1 and HW3 NUC just to make sure.
Since I went through all those 'destructive' troubleshooting steps I really can't imagine where that stale LG BD drive info keeps coming back from.
Any assistance will be greatly appreciated.
Thanks, removing old EFI entries would be an obvious solution, but I forgot to mention in my original post that I thought about that and swapped SSD to one that was never used in that NUC before. So I assume the offending EFI entry shouldn't be on it. Or does the NUC (or any PC) re-populate the EFI partition automatically with bogus entries like the one in my case?
And so despite having swapped SSD, the condition still exists, and USB boot fails.
Wow, the solution outlined in the first video link provided actually worked. The offending LG Blu-Ray drive entry indeed showed up in the list and removing it per the video instructions was easy.
Here is the link again for everyone else's benefit:
The title is Remove old EFI entry from Boot Menu
BIG THANKS to Leon Waksman for coming to the rescue so quickly.