diff --git a/configuration/rescue-cd.nix b/configuration/rescue-cd.nix
index ee2c7c2a510..9a28e671989 100644
--- a/configuration/rescue-cd.nix
+++ b/configuration/rescue-cd.nix
@@ -18,9 +18,9 @@ rec {
       # The label used to identify the installation CD.
       rootLabel = "NIXOS";
       extraTTYs = [7 8]; # manual, rogue
-      extraModulePackages = pkgs: [system.kernelPackages.aufs];
+      extraModulePackages = [system.kernelPackages.aufs];
       
-      kernelPackages = pkgs: pkgs.kernelPackages_2_6_25;
+      kernelPackages = pkgs.kernelPackages_2_6_25;
       
       initrd = {
         extraKernelModules = [
@@ -172,7 +172,7 @@ rec {
     };
  
     environment = {
-      extraPackages = pkgs: [
+      extraPackages = [
         pkgs.vim
         pkgs.subversion # for nixos-checkout
         pkgs.w3m # needed for the manual anyway
diff --git a/system/options.nix b/system/options.nix
index df30b8e011a..4df60a5150c 100644
--- a/system/options.nix
+++ b/system/options.nix
@@ -16,7 +16,7 @@ let
   # backward here means that expression could either be a value or a
   # function which expects to have a pkgs argument.
   optionalPkgs = name: x:
-    if __isFunction x
+    if builtins.isFunction x
     then obsolete "notation" (name: x pkgs) name
     else x;