I now have a working, text-based Arch Linux installation on the laptop in question. Secure Boot is off for the moment. I plan next to install a graphical desktop environment and the Orca screen reader. (I've raised questions on the relevant mailing list.) This laptop has two GPUs, an Intel GPU and an NVidia GPU. I think it's NVidia Optimus. Where would I find current information on how to configure it? I would prefer not to take the proprietary driver route (i.e., Nouveau drivers would be best, if possible). Arch Linux has the bbswitch package, which is for Optimus laptops. Although I can't see what is on screen, other people may need to look at it, and I also may wish to give presentations using an external display. So it's worth getting the graphics working.