Thanks to the incredible combination of Lenovo and Nvidia, I cannot remove the Microsoft keys from my laptop. Not because Microsoft backdoored my computer, but because the Nvidia boot ROM is signed by an MS cert and that runs before you can access the UEFI setup.

I hope the firmware either doesn't check the expiry date or that the firmware itself has been upgraded, or several years worth of Thinkpad are about to stop booting in the near future.