diff --git a/nixbld-etc-nixos/configuration.nix b/nixbld-etc-nixos/configuration.nix
index 9d556d3..d3e853e 100644
--- a/nixbld-etc-nixos/configuration.nix
+++ b/nixbld-etc-nixos/configuration.nix
@@ -287,6 +287,7 @@ in
   boot.kernel.sysctl."kernel.dmesg_restrict" = true;
   services.udev.packages = [ pkgs.sane-backends ];
 
+  nix.package = pkgs.nix_2_4;
   nix.distributedBuilds = true;
   nix.nrBuildUsers = 64;
   nix.trustedUsers = ["sb"];
@@ -450,10 +451,10 @@ in
   };
  
   nixpkgs.config.packageOverrides = super: let self = super.pkgs; in {
-    nix = super.nix.overrideAttrs(oa: {
-      patches = oa.patches or [] ++ [ ./nix-networked-derivations.diff ];
+    nix_2_4 = super.nix_2_4.overrideAttrs(oa: {
+      patches = oa.patches or [] ++ [ ./nix-3-networked-derivations.patch ];
     });
-    nixFlakes = super.nixFlakes.overrideAttrs(oa: {
+    nixUnstable = super.nixUnstable.overrideAttrs(oa: {
       patches = oa.patches or [] ++ [ ./nix-3-networked-derivations.patch ];
     });
     hydra-unstable = super.hydra-unstable.overrideAttrs(oa: {
diff --git a/nixbld-etc-nixos/nix-networked-derivations.diff b/nixbld-etc-nixos/nix-networked-derivations.diff
deleted file mode 100644
index 10d9c49..0000000
--- a/nixbld-etc-nixos/nix-networked-derivations.diff
+++ /dev/null
@@ -1,83 +0,0 @@
-diff -Naur nix-2.3.10.orig/src/libstore/build.cc nix-2.3.10/src/libstore/build.cc
---- nix-2.3.10.orig/src/libstore/build.cc	1970-01-01 08:00:01.000000000 +0800
-+++ nix-2.3.10/src/libstore/build.cc	2021-04-24 16:17:08.778875340 +0800
-@@ -840,9 +840,16 @@
-     /* Whether this is a fixed-output derivation. */
-     bool fixedOutput;
- 
-+    bool networked;
-+
-     /* Whether to run the build in a private network namespace. */
-     bool privateNetwork = false;
- 
-+    bool allowNetwork()
-+    {
-+        return fixedOutput || networked;
-+    }
-+
-     typedef void (DerivationGoal::*GoalState)();
-     GoalState state;
- 
-@@ -1181,6 +1188,8 @@
- {
-     trace("have derivation");
- 
-+    fixedOutput = drv->isFixedOutput();
-+
-     retrySubstitution = false;
- 
-     for (auto & i : drv->outputs)
-@@ -1197,6 +1206,8 @@
- 
-     parsedDrv = std::make_unique<ParsedDerivation>(drvPath, *drv);
- 
-+    networked = parsedDrv->getBoolAttr("__networked");
-+
-     /* We are first going to try to create the invalid output paths
-        through substitutes.  If that doesn't work, we'll build
-        them. */
-@@ -1932,7 +1943,7 @@
-         else if (settings.sandboxMode == smDisabled)
-             useChroot = false;
-         else if (settings.sandboxMode == smRelaxed)
--            useChroot = !fixedOutput && !noChroot;
-+            useChroot = !allowNetwork() && !noChroot;
-     }
- 
-     if (worker.store.storeDir != worker.store.realStoreDir) {
-@@ -2109,7 +2120,7 @@
-                 "nogroup:x:65534:\n") % sandboxGid).str());
- 
-         /* Create /etc/hosts with localhost entry. */
--        if (!fixedOutput)
-+        if (!allowNetwork())
-             writeFile(chrootRootDir + "/etc/hosts", "127.0.0.1 localhost\n::1 localhost\n");
- 
-         /* Make the closure of the inputs available in the chroot,
-@@ -2323,7 +2334,7 @@
-            us.
-         */
- 
--        if (!fixedOutput)
-+        if (!allowNetwork())
-             privateNetwork = true;
- 
-         userNamespaceSync.create();
-@@ -2534,7 +2545,7 @@
-        to the builder is generally impure, but the output of
-        fixed-output derivations is by definition pure (since we
-        already know the cryptographic hash of the output). */
--    if (fixedOutput) {
-+    if (allowNetwork()) {
-         for (auto & i : parsedDrv->getStringsAttr("impureEnvVars").value_or(Strings()))
-             env[i] = getEnv(i);
-     }
-@@ -2823,7 +2834,7 @@
-             /* Fixed-output derivations typically need to access the
-                network, so give them access to /etc/resolv.conf and so
-                on. */
--            if (fixedOutput) {
-+            if (allowNetwork()) {
-                 ss.push_back("/etc/resolv.conf");
- 
-                 // Only use nss functions to resolve hosts and