Booting to blinking cursor after nixos-rebuild --upgrade

Help
1

I’m running NixOS with the Cosmic desktop environment, which I understand is experimental in nature. However this is (was) running on both my personal laptop and on my work desktop. I recently tried to adjust my configuration for my laptop because I realized that my GPU might not be configured correctly.

So I adjusted the config file in accordance with the NixOS wiki (adding hardware.graphics.enable = true; and hardware.graphics.enable32Bit=true; etc.) and ran `sudo nixos-rebuild boot --upgrade’

When I restarted my computer I arrived at a black screen with a blinking cursor in the corner. I’m able to boot into a TTY and edit things, but no amount of tinkering, going back, changing channels, has been able to unravel this issue.

Sorry if this is light on details, I can try to add a snippet of my config below:

{ config, pkgs, ... }:
let
     home-manager = builtins.fetchTarball "https://github.com/nix-community/home-manager/archive/release-25.11.tar.gz";
in
{
     imports = 
          [ ./hardware-configuration.nix
          (import "${home-manager}/nixos")
          ];

      boot.loader.systemd-boot = {
          enable = true;
          consoleMode = "2";
      };
      boot.loader.efi.canTouchEfiVariables = true;

      # This was the original graphics line before I tried to adjust
      boot.initrd.kernelModules = ["amdgpu"];

       ### all the other setup ####

      services.displayManager.cosmic-greeter.enable = true;
      services.desktopManager.cosmic.enable = true;

      ### rest of the config + home manager ###

     services.asusd.enable = true;
     services.expressvpn.enable = true;
     services.seatd.enable = true;
     services.tailscale.enable = true;
     services.udisks2.enable = true;

     system.stateVersion = "25.11";
}

Thank you in advance and please let me know if other info is necessary

2

That config is definitely too little and almost certainly does not contain whatever is going wrong.

If you log into the tty, and use journalctl -e and journalctl --user -e, does that show you your error messages?

By the way, replace this:

With this:

let
     home-manager = builtins.fetchTarball {
       url = "https://github.com/nix-community/home-manager/archive/release-25.11.tar.gz";
       hash = "";
     };
in

And then update the hash with what nix spews at you. It will increase your build speeds by a few tens of seconds to minutes, and make your builds actually reproducible.

3

Thank you for taking the time to reply. So when I check journalctl -e it looks like there may be an error:

... .cosmic-comp-wrapped[2224]: Unable to become drm master, assuming unprivileged mode
.cosmic-comp-wrapped[2224]: thread 'main' panicked at 'Failed to load LibEGL: DlOpen { desc: "libEGL.so.1: cannot open shared object: No such file or directory" }': /build/cosmic...
.... # A bunch of error messages #
... greetd.service: Start request repeated too quickly
... greetd.service: Failed with result 'start-limit-hit'.
... systemd[1]: Failed to start greetd.service.

So it seems like there’s an issue with greetd starting.
I do have the services.seatd.enable = true;, but I don’t know if there’s another issue somewhere.

Cheers!

4

Looks more like your cosmic binary was built with libraries in weird places, but it’s hard to tell with all the context you elided. Might also be a misconfigured driver.

Do you have overlays, nix-ld, or are you running a cosmic binary you downloaded or suchlike?