diff --git a/nix/hosts/t490/configuration.nix b/nix/hosts/t490/configuration.nix
index 88a55c5..8163650 100644
--- a/nix/hosts/t490/configuration.nix
+++ b/nix/hosts/t490/configuration.nix
@@ -51,6 +51,7 @@
   };
 
   environment.systemPackages = with pkgs; [
+    bc # Needed for ./displayselect script.
     gtypist
     newsboat
     pam_gnupg