diff --git a/hosts/fruitbook/configuration.nix b/hosts/fruitbook/configuration.nix
index d67dd64..17f6c4d 100644
--- a/hosts/fruitbook/configuration.nix
+++ b/hosts/fruitbook/configuration.nix
@@ -11,7 +11,6 @@
     wifi.enable = true;
     stylix.enable = true;
     niri.enable = true;
-    xbacklight-permissions.enable = true;
     users.users = [
       "crumb"
     ];
diff --git a/hosts/fruitbook/disks.nix b/hosts/fruitbook/disks.nix
new file mode 100755
index 0000000..9d4f33a
--- /dev/null
+++ b/hosts/fruitbook/disks.nix
@@ -0,0 +1,73 @@
+# sudo nix --experimental-features "nix-command flakes" run github:nix-community/disko/latest -- --mode disko /persist/dots/hosts/nixos-testbed/disko-config.nix
+# time sudo nixos-install --flake /persist/dots#nixos-testbed
+{ lib, ... }:
+{
+  # imports = [ disko.nixosModules.disko ];
+  boot.initrd.supportedFilesystems.btrfs = true;
+  boot.supportedFilesystems.btrfs = true;
+
+  # From Impermanence's README: "Important note: Make sure your persistent
+  # volumes are marked with neededForBoot, otherwise you will run into
+  # problems."
+  fileSystems."/persist".neededForBoot = true;
+
+  disko.devices = {
+    disk = {
+      bootroot = {
+        type = "disk";
+        device = "/dev/disk/by-id/ata-APPLE_SSD_SM0512G_S29ANYAH526520-part4";
+        content = {
+          type = "gpt";
+          partitions = {
+            ESP = {
+              size = "512M";
+              type = "EF00";
+              content = {
+                type = "filesystem";
+                format = "vfat";
+                mountpoint = "/boot";
+                mountOptions = [ "umask=0077" ];
+              };
+            };
+            root = {
+              size = "100%";
+              content = {
+                type = "btrfs";
+
+                mountpoint = "/partition-root";
+                swap.swapfile.size = "4G";
+
+                # Override existing partitions.
+                extraArgs = [ "-f" ];
+
+                # Subvolumes must set a mountpoint in order to be mounted,
+                # *unless their parent is mounted*.
+                subvolumes = {
+                  # Subvolume names do not necessarily correspond to
+                  # mountpoints, despite the structural resemblance to a file
+                  # path.
+                  "/rootfs" = {
+                    mountpoint = "/";
+                  };
+                  "/nix" = {
+                    mountpoint = "/nix";
+                  };
+                  "/persist" = {
+                    mountpoint = "/persist";
+                  };
+                  "/persist/home" = {
+                    mountpoint = "/persist/home";
+                  };
+                  "/swap" = {
+                    mountpoint = "/.swapvol";
+                    swap.swapfile.size = "4G";
+                  };
+                };
+              };
+            };
+          };
+        };
+      };
+    };
+  };
+}
diff --git a/modules/home/users/crumb/niri.nix b/modules/home/users/crumb/niri.nix
index 12806ca..972042a 100644
--- a/modules/home/users/crumb/niri.nix
+++ b/modules/home/users/crumb/niri.nix
@@ -73,7 +73,7 @@ in {
 
         spawn-at-startup =
           [{ command = [ "${pkgs.swaynotificationcenter}/bin/swaync" ]; }
-           { command = [ (lib.getExe pkgs.gammastep) "-o" "-O" "4000k"
+           { command = [ "${pkgs.gammastep}/bin/gammastep" "-o" "-O" "4000k"
                          "-b" "0.9:0.9" "-l" "0:0"]; }]
           ++ lib.optional
             (! builtins.isNull cfg.wallpaper)
@@ -175,7 +175,7 @@ in {
               { title = "Discord.*@"; }
             ];
             excludes = [
-              # ...except when explicitly targeting the window.
+              # ... except when explicitly targeting the window.
               { is-window-cast-target = true; }
             ];
             block-out-from = "screen-capture";
@@ -226,9 +226,8 @@ in {
         binds = {
           "Mod+Q".action.close-window = [];
           "Mod+Shift+Q".action.quit = [];
-          "Mod+Ctrl+L".action.spawn = [ (lib.getExe pkgs.swaylock) ];
-          "Mod+D".action.spawn = [ (lib.getExe pkgs.fuzzel) ];
-          "XF86LaunchB".action.spawn = [ (lib.getExe pkgs.fuzzel) ];
+          "Mod+Ctrl+L".action.spawn = ["${pkgs.swaylock}/bin/swaylock"];
+          "Mod+D".action.spawn = ["${pkgs.fuzzel}/bin/fuzzel"];
           "Mod+Shift+Slash".action.show-hotkey-overlay = [];
 
           # Powers off the monitors.  They will be powered back on upon any
@@ -280,12 +279,7 @@ in {
           "Mod+Shift+J".action.move-window-down = []; 
           "Mod+Shift+K".action.move-window-up = []; 
           "Mod+Shift+L".action.move-column-right = []; 
-
-          "XF86MonBrightnessDown".action.spawn =
-            ["${lib.getExe pkgs.acpilight}" "-dec" "10"];
-          "XF86MonBrightnessUp".action.spawn =
-            ["${lib.getExe pkgs.acpilight}" "-inc" "10"];
-
+            
           "Mod+1".action.focus-workspace = [1];
           "Mod+2".action.focus-workspace = [2];
           "Mod+3".action.focus-workspace = [3];
diff --git a/modules/nixos/xbacklight-permissions.nix b/modules/nixos/xbacklight-permissions.nix
deleted file mode 100644
index 7080816..0000000
--- a/modules/nixos/xbacklight-permissions.nix
+++ /dev/null
@@ -1,35 +0,0 @@
-{ config, lib, pkgs, ... }:
-
-let cfg = config.sydnix.xbacklight-permissions;
-in {
-  options.sydnix.xbacklight-permissions = {
-    enable =
-      lib.mkEnableOption "the user group that is allowed to use xbacklight";
-    group = lib.mkOption {
-      type = lib.types.str;
-      default = "xbacklight";
-    };
-    paths = lib.mkOption {
-      type = with lib.types; listOf str;
-      default = [
-        "/sys/class/backlight/intel_backlight/brightness"
-      ];
-    };
-  };
-
-  config = lib.mkIf cfg.enable {
-    users.groups.${cfg.group} = {};
-
-    systemd.tmpfiles.settings."50-xbacklight" =
-      lib.mergeAttrsList
-        (builtins.map
-          (path: {
-            ${path}.z = {
-              inherit (cfg) group;
-              mode = "0664";
-              user = "root";
-            };
-          })
-          cfg.paths);
-  };
-}
diff --git a/users/crumb/default.nix b/users/crumb/default.nix
index 42f3102..04c99ef 100755
--- a/users/crumb/default.nix
+++ b/users/crumb/default.nix
@@ -3,13 +3,7 @@
     isNormalUser = true;
     # TODO: Don't hard-code `persist`.  Use
     # config.sydnix.impermanence.persistGroupName.
-    extraGroups = [
-      "wheel"
-      "persist"
-      "input"
-      "networkmanager"
-      "xbacklight"
-    ];
+    extraGroups = [ "wheel" "persist" "input" "networkmanager" ];
     initialHashedPassword =
       "$y$j9T$aEFDDwdTZbAc6VQRXrkBJ0$K8wxTGTWDihyX1wxJ.ZMH//wmQFfrGGUkLkxIU0Lyq8";