Try this it may help with asus usb. Shut down the pc turn the psu off and remove the power cable(very important) from the psu for few minutes. If you don't mind clear cmos before this, or do it without clearing and see if it helps if not then clear cmos and redo it. On rampage v extreme it has on bios a option to not support any usb devices till OS boots, for faster boot times, or a partial support of usb devices (like mouse and kb) check them too, before and after.
Had the same issue with a k95 rgb, a clear cmos and removing any power of the system helped, even I did that to eliminate a exclamation usb device on device manager (ghost device) but helped with the k95 that I had to switch to bios mode to get recognized on boot to enter bios. Now no need to switch on mode 1 and I can enter bios with it.
Hope it will help you guys.