Download the file again and copy it to an empty FAT32 USB flash drive. Then, try the BIOS recovery method with the power button menu or by removing the jumper.
thanks for the fast reply. I had no luck, though:
i) First I did as you advised above. In the Menu, I selected [F4] for BIOS recovery, but the screen went black after about 1 second and the NUC turned off. I think it didn't find the FY0051.BIO file.
ii) Then, I copied the FY0051.BIO to the hard disk and repeated sequence i): same result.
iii) Finally, I powered up the NUC normally, pressed [F2] to enter the BIOS and selected "update BIOS" from the TOOLS menu. Surprisingly, the USB stick's file system was listed here and I could select the FY0051.BIO file. I initiated the update, but it failed with the error message above (attached image).
What is going wrong and how can I upgrade the BIOS?
You may try removing the board from the case and disconnecting the battery cable from the header for twenty minutes, connect it back and try again.
Are you trying to solve an issue by updating the BIOS? The last option could be replacing the unit with your nearest Intel support team.
You may try removing the board......
This is what I did, removed the BIOS jumper and then tried a BIOS recovery update. The NUC didn't see the .BIO file on the USB stick first, but after a few repetitions I tried sequence iii) above and was able to flash the FY0051.BIO file without errors.
I think this is very strange; but finally I suceeded in flashing the 0051 BIOS.