From the article

> Microsoft holding back support is the xHCI USB controller in sixth-generation Skylake and seventh-generation Kaby Lake: Windows 7 doesn't support that USB hardware, so installing the operating system from a USB stick using those chips is tricky. Intel provides xHCI drivers for Windows 7 once it's up and running.

AFAIK, consumer editions of Windows 7 never even officially came in a "USB stick" form factor. It has always been on a DVD.

So the more salient question would be: is it possible to plug in a USB external ODD to a Kaby Lake laptop, pop the Windows 7 DVD in it, and install from it? Or is it just as "tricky" as installing from a USB stick?

How would the usb ODD work without a working usb controller?

How can one boot from an USB DVD then, sans an OS?

I don't know what the newer systems do, but on older ones that had USB boot support, the BIOS has a basic USB driver that lets even DOS apps access CD/DVD/USB media via the traditional INT 13H interface.

Several motherboard vendors provide tools to patch Windows 7 ISOs to include Skylake USB3 drivers, and you can include them by hand if you need to.

ASRock's tool for my Skylake mainboard worked fine, could install off its USB3.1 port.