I put together a usb stick with win7x64 on it, and the intel usb3.0 driver files(.inf and .sys, et.al.) on a cd.
The installation progressed to the "where are the unknown drivers" screen, which gives options to point to them including the cd/dvd drive..
The cd's usb drivers were accepted, the mouse turned on(!) and the everything loaded in followed by the Realtek audio and Atheros wifi drivers.
After a shutdown it was impossible to restart the unit. It would not go past the logo splash screen with F2, or boot.
The laptop restarted several times during the Win7 installation and after the drivers, but now is a doorstop.
Is it possible that Win10 modifies the bios to prevent this downgrade?