No, nothing special to set in SY BIOS. Leave both Legacy and UEFI enabled when you install Windows 7. Make sure you have the USB 3.0 drivers in your Windows 7 installation images; Windows 7 does not have native support for USB 3.0 and all USB ports in the SY NUC (even the USB 2.0 ports) go through a USB 3.0 root hub so the drivers are necessary if you want keyboard and mouse support to work. There are a whole slew of discussions that can point you to instructions for setting up the Windows 7 Installation images; consult them now...
Hope this helps,
Thank you for your colaboration N. Scott Pearson.
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I was curious if you were able to get the desired configuration in your Intel® NUC Kit NUC6i5SYH.
Did it work properly? Please let me know :)