diff --git a/docker.nix b/docker.nix
index b23a9637f..27616bcd8 100644
--- a/docker.nix
+++ b/docker.nix
@@ -157,7 +157,7 @@ let
 
   nixConfContents =
     (lib.concatStringsSep "\n" (
-      lib.mapAttrsFlatten (
+      lib.mapAttrsToList (
         n: v:
         let
           vStr = if builtins.isList v then lib.concatStringsSep " " v else v;