diff --git a/modules/installer/grub/grub-menu-builder.sh b/modules/installer/grub/grub-menu-builder.sh
index cf2041002e74..ecb69ceb263f 100644
--- a/modules/installer/grub/grub-menu-builder.sh
+++ b/modules/installer/grub/grub-menu-builder.sh
@@ -216,6 +216,10 @@ extraEntries=`cat <<EOF
 EOF`
 
 
+cat >> $tmp <<EOF
+@extraConfig@
+EOF
+
 if test -n "@extraEntriesBeforeNixOS@"; then 
     echo "$extraEntries" >> $tmp
 fi
diff --git a/modules/installer/grub/grub.nix b/modules/installer/grub/grub.nix
index 4217e0d481c4..40c2ca606751 100644
--- a/modules/installer/grub/grub.nix
+++ b/modules/installer/grub/grub.nix
@@ -12,7 +12,8 @@ let
     inherit grub;
     inherit (pkgs) bash;
     path = [pkgs.coreutils pkgs.gnused pkgs.gnugrep];
-    inherit (config.boot.loader.grub) copyKernels extraEntries extraEntriesBeforeNixOS
+    inherit (config.boot.loader.grub) copyKernels
+      extraConfig extraEntries extraEntriesBeforeNixOS
       splashImage configurationLimit version default timeout;
   };
   
@@ -67,6 +68,15 @@ in
         '';
       };
 
+      extraConfig = mkOption {
+        default = "";
+        example = "serial; terminal_output.serial";
+        description = ''
+          Additional GRUB commands inserted in the configuration file
+          just before the menu entries.
+        '';
+      };
+
       extraEntries = mkOption {
         default = "";
         example = ''
diff --git a/tests/installer.nix b/tests/installer.nix
index a15b5587511b..1f9ada808b26 100644
--- a/tests/installer.nix
+++ b/tests/installer.nix
@@ -40,6 +40,7 @@ let
 
         boot.loader.grub.version = 2;
         boot.loader.grub.device = "/dev/vda";
+        boot.loader.grub.extraConfig = "serial; terminal_output.serial";
         boot.initrd.kernelModules = [ "ext3" ];
       
         fileSystems = [ ${fileSystems} ];