diff --git a/boot/boot-stage-1.nix b/boot/boot-stage-1.nix
index 7b7f5503d0b..46d4a52c6c9 100644
--- a/boot/boot-stage-1.nix
+++ b/boot/boot-stage-1.nix
@@ -148,7 +148,7 @@ rec {
 
     # !!! copy&pasted from upstart-jobs/filesystems.nix.
     mountPoints =
-      if fileSystems == []
+      if fileSystems == null
       then abort "You must specify the fileSystems option!"
       else map (fs: fs.mountPoint) fileSystems;
     devices = map (fs: if fs ? device then fs.device else "/dev/disk/by-label/${fs.label}") fileSystems;
diff --git a/system/options.nix b/system/options.nix
index 53a3d11d7f6..68cad69d0d7 100644
--- a/system/options.nix
+++ b/system/options.nix
@@ -303,7 +303,7 @@ in
 
 
   fileSystems = mkOption {
-    default = [];
+    default = null;
     example = [
       { mountPoint = "/";
         device = "/dev/hda1";