I followed links 1 and 2 and got Windows 7 圆4 installed. You need to download/run the KB 947821: System Update Readiness tool Once Windows is installed, the Windows Update will NOT UPDATE.You then need to use the Deployment Image Servicing and Management Tool and modify the boot.wim and install.wim file to the SOURCES folder on the USB install drive. Windows 7 also did not trust the files and you need to unblock them. This involves downloading the USB 3.0 drivers from Intel. You need to add the USB 3.0 drivers to the installation.Creating an ISO from the DVD would not work with the USB/DVD Download Tool. You need to transfer the Windows 7 installation to a bootable USB drive.Therefore, you cannot use a USB mouse or keyboard during installation. Windows 7 doesn't support USB 3.0 on the installation disks.You can purchase it here: USB A Female to 1 X 4 Pin Internal USB Connector 1.25 mm Pitch
The internal ports require a non standard 4x1.25 mm header to USB adapter. I was able to get Windows 7 圆4 working on the NUC6i5SYH.