usb - How to install Windows 7 on X1 Carbon 20FB (driver issue)?

I want to install Windows 7 on a Lenovo Thinkpad X1 Carbon 20FB-002LUS. I created a bootable USB stick with woeusb and the Windows 7 installation medium. However, when I boot from it I get a driver error:

A required CD/DVD drive device driver is missing. If you have a driver floppy disk, CD, DVD, or USB flash drive, please insert it now.

How do I figure out which specific driver is missing (I'm guessing USB 3.0)? How can I provide the driver?

I have access to a Linux desktop (not intel).

Answer

The problem turned out to be (after trial and error) missing USB 3.0 drivers, which is a very common issue when installing Win7 on newer systems.

The drivers have to be injected into the USB (specifically, I think boot.wim). Microsoft recommend dism to do this. I had little patience for Windows's horrendous command line so I was able to find a GUI wrapper for DISM: https://github.com/mikecel79/DISMGUI/releases

Using this I added the USB 3.0 drivers and the installation proceeded successfully. Funnily enough, the installed Windows 7 did not have USB 3.0 drivers and could not read the USB drive it had just been installed from. There was a similar story with the memory card reader, the wireless adapter, as well as the dock (which has an ethernet port). So I had effectively painted myself into a corner, as I needed drivers to access any external resources but I needed to access the resources to get the drivers.

I was able to resolve the catch 22 by creating a Linux live USB. I booted the laptop from this and connected to the internet (note that I needed a special version of the Linux ISO which contained my non-free wireless driver). Then I downloaded the Windows USB 3.0 driver and put on the Window drive using the Linux live environment (I should have added the wireless driver too, but I wasn't sure which one was the correct one). After this I booted into Windows, installed the USB 3.0 driver, and the rest was straightforward.

You might ask, was it worth all that effort? Absolutely, Windows 10 is an godawful OS and Windows 7 worked beautifully.