use nixos-hardware from flake inputs

flake.nix

@@ -0,0 +1,19 @@
+{
+  description = "NixOS system flake";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-22.11";
+    nixos-unstable.url = "github:NixOS/nixpkgs/nixos-unstable";
+    nixos-hardware.url = "github:NixOS/nixos-hardware/master";
+  };
+
+  outputs = { self, nixpkgs, ... }@inputs: {
+
+    nixosConfigurations.thinknix = nixpkgs.lib.nixosSystem {
+      system = "x86_64-linux";
+      modules = [ ./nixos/configuration.nix ];
+      # necessary to make the top-level inputs available to system configuration
+      specialArgs = { inherit inputs; };
+    };
+  };
+}

nixos/configuration.nix

@@ -2,10 +2,10 @@
 # your system.  Help is available in the configuration.nix(5) man page
 # and in the NixOS manual (accessible by running ‘nixos-help’).
 
-{ config, pkgs, ... }:
+{ config, pkgs, lib, inputs, ... }:
 
 let
-  unstable = import <nixos-unstable> { };
+  unstable = inputs.nixos-unstable;
   localfork = import /home/spiollinux/src/nixpkgs { };
 
 in
@@ -234,15 +234,22 @@ in
   # Enable all sysrq functions (useful to recover from some issues):
   boot.kernel.sysctl."kernel.sysrq" = 1; # NixOS default: 16 (only the sync command)
 
+  nix = {
+    # expose all flake inputs through nix Path and registry
+    registry = (lib.mapAttrs (_: value: { flake = value; }) inputs) // {
+      nixpkgs.flake = inputs.nixpkgs;
+    };
+    nixPath = lib.mapAttrsToList (key: value: "${key}=${value.to.path}") config.nix.registry;
   # keep build-time deps around for offline-rebuilding
-  nix.settings = {
-    # keep around all inputs necessary for offline-rebuilding the system
-    keep-outputs = true;
-    keep-derivations = true;
-    trusted-users = [ "spiollinux" ];
-    experimental-features = [ "nix-command" "flakes" ];
-    # use all cores for building
-    cores = 0;
+    settings = {
+      # keep around all inputs necessary for offline-rebuilding the system
+      keep-outputs = true;
+      keep-derivations = true;
+      trusted-users = [ "spiollinux" ];
+      experimental-features = [ "nix-command" "flakes" ];
+      # use all cores for building
+      cores = 0;
+    };
   };
   # override tmpdir for daemon
   #systemd.services.nix-daemon.environment.TMPDIR = "/var/tmp";

nixos/hardware-configuration.nix

@@ -1,4 +1,4 @@
-{ config, lib, pkgs, ... }:
+{ config, lib, pkgs, modulesPath, inputs, ... }:
 
 
 let
@@ -7,13 +7,8 @@ in
 {
   imports =
     [
-      <nixpkgs/nixos/modules/installer/scan/not-detected.nix>
-      (
-        builtins.fetchGit {
-          url = "https://github.com/NixOS/nixos-hardware";
-          rev = "a4bc66709604ab78abc575b60baa6d23ae027a59";
-        } + "/lenovo/thinkpad/t440s"
-      )
+      (modulesPath + "/installer/scan/not-detected.nix")
+      (inputs.nixos-hardware + "/lenovo/thinkpad/t440s")
     ];
 
   boot.initrd.availableKernelModules = [ "xhci_pci" "ehci_pci" "ahci" "usb_storage" "sd_mod" "rtsx_pci_sdmmc" ];