I installed NixOS on a RaspberryPi 4 around January using the instructions on the wiki and an SD image from hydra. (I’ve forgotten which commit I used.) I’ve done a few upgrades on the unstable channel, and things are basically great. I’ve been slowly learning and improving my setup - add a user, load keyboard map, set console fonts, X with i3, use Home Manager to configure neovim, etc. The more I learn about Nix and NixOS, the more I think it is amazing! (I still have a long way to go to really understand Nix and NixOS.)
My next adventure is getting the USB keyboard to work during early boot so I can select a previous generation. Currently, I get a timeout (-110) detecting xhci. I think this is related to a change in handling the vl805 firmware and think the issue is fixed in recent versions of U-Boot. I appear to have U-Boot 2020.10 and think unstable has 2021.04 which has the fix. I would like to upgrade my system to that version. However, I can’t figure out how to do that.
Various searches have lead me to
pkgs/misc/uboot/default.nix. I might almost see how that gets U-Boot on the SD image, but I don’t see how to update U-Boot on my system that started out life as that SD image.
Does anyone have any pointers or suggestions?
Thank you for reading my question!