diff --git a/hosts/yodaTab/configuration.nix b/hosts/yodaTab/configuration.nix
index a7d4339..7113772 100644
--- a/hosts/yodaTab/configuration.nix
+++ b/hosts/yodaTab/configuration.nix
@@ -58,4 +58,9 @@ in
   networking.hostName = "yodaTab";
   services.openssh.ports = [ 22 ];
   boot.initrd.network.ssh.port = 22;
+
+  # Allow unfree packages.
+  nixpkgs.config.allowUnfree = true;
+
+  boot.kernelPackages = pkgs.linuxPackages_latest;
 }
diff --git a/hosts/yodaTux/configuration.nix b/hosts/yodaTux/configuration.nix
index 5546af6..c363710 100644
--- a/hosts/yodaTux/configuration.nix
+++ b/hosts/yodaTux/configuration.nix
@@ -58,4 +58,21 @@ in
   networking.hostName = "yodaTux";
   services.openssh.ports = [ 22 ];
   boot.initrd.network.ssh.port = 22;
+
+  # Allow unfree packages.
+  nixpkgs.config.allowUnfree = false;
+
+  # List all available kernel versions:
+  #   `nix repl` -> `:l <nixpkgs>` -> `pkgs.linuxPackages` and press `TAB`
+  # Default.
+  #boot.kernelPackages = pkgs.linuxPackages;
+  # Latest.
+  boot.kernelPackages = pkgs.linuxPackages_latest;
+  # Hardened.
+  # https://archlinux.org/packages/extra/x86_64/linux-hardened/
+  # -> https://github.com/anthraxx/linux-hardened
+  #boot.kernelPackages = pkgs.linuxPackages_hardened;
+  # Free/Libre.
+  # https://en.wikipedia.org/wiki/Linux-libre
+  #boot.kernelPackages = pkgs.linuxPackages-libre;
 }
diff --git a/hosts/yodaYoga/configuration.nix b/hosts/yodaYoga/configuration.nix
index ec3cc17..1be910d 100644
--- a/hosts/yodaYoga/configuration.nix
+++ b/hosts/yodaYoga/configuration.nix
@@ -60,4 +60,9 @@ in
   networking.hostName = "yodaYoga";
   services.openssh.ports = [ 2224 ];
   boot.initrd.network.ssh.port = 2225;
+
+  # Allow unfree packages.
+  nixpkgs.config.allowUnfree = false;
+
+  boot.kernelPackages = pkgs.linuxPackages;
 }
diff --git a/modules/base.nix b/modules/base.nix
index 96f5eb8..0221ee7 100644
--- a/modules/base.nix
+++ b/modules/base.nix
@@ -46,9 +46,6 @@
   # Configure console keymap.
   console.keyMap = "de-latin1-nodeadkeys";
 
-  # Allow unfree packages.
-  nixpkgs.config.allowUnfree = true;
-
   # Define a user account. Don't forget to set a password with `passwd`.
   users.users.yoda = {
     isNormalUser = true;