I can't update the BIOS (28-->33) on my NUC6i5SYH. I've tried the .bio via F7 and the visual bios, as well as the dos disk method. After starting the update the unit powers down, the yellow light flashes and nothing happens for hours. I can restart the nuc by holding power down. The first boot gives me three beeps with blue light. After holding power again it boots up, with bios 28. Any ideas?
I had a similar issue, when my NUC was hooked up with the mDP cable in UHD 60hz mode... it fails to boot when it's flashing with orange.
I disabled the 60hz function of my TV and it switched back to some other kind of resolution, after that updating worked just fine.