diff --git a/checks/installation/flake-module.nix b/checks/installation/flake-module.nix
index 062486e86..35632bb02 100644
--- a/checks/installation/flake-module.nix
+++ b/checks/installation/flake-module.nix
@@ -18,16 +18,6 @@ let
         pkgs.bubblewrap
       ] ++ builtins.map (i: i.outPath) (builtins.attrValues self.inputs);
       closureInfo = pkgs.closureInfo { rootPaths = dependencies; };
-      # with Nix 2.24 we get:
-      # vm-test-run-test-installation> installer # error: sized: unexpected end-of-file
-      # vm-test-run-test-installation> installer # error: unexpected end-of-file
-      # This seems to be fixed with Nix 2.26
-      # Remove this line once `pkgs.nix` is 2.26+
-      nixPackage =
-        assert
-          lib.versionOlder pkgs.nix.version "2.26"
-          && lib.versionAtLeast pkgs.nixVersions.latest.version "2.26";
-        pkgs.nixVersions.latest;
     in
     {
       imports = [
@@ -49,7 +39,6 @@ let
       # both installer and target need to use the same diskImage
       virtualisation.diskImage = "./target.qcow2";
       virtualisation.memorySize = 3048;
-      nix.package = nixPackage;
       nix.settings = {
         substituters = lib.mkForce [ ];
         hashed-mirrors = null;
diff --git a/flake.lock b/flake.lock
index bc9db94ed..cf4b7b10d 100644
--- a/flake.lock
+++ b/flake.lock
@@ -107,10 +107,10 @@
     "nixpkgs": {
       "locked": {
         "lastModified": 315532800,
-        "narHash": "sha256-ItICEnpINZw5JS7D3OS8Yl7fjJsJK/xSIQKdLPEYWDU=",
-        "rev": "b2b0718004cc9a5bca610326de0a82e6ea75920b",
+        "narHash": "sha256-G1wiMQR6wAFxbIb/Gyh9W9Y5BSXOo0C4C5B8iui/kNo=",
+        "rev": "d19cf9dfc633816a437204555afeb9e722386b76",
         "type": "tarball",
-        "url": "https://releases.nixos.org/nixpkgs/nixpkgs-25.05pre780817.b2b0718004cc/nixexprs.tar.xz"
+        "url": "https://releases.nixos.org/nixpkgs/nixpkgs-25.05pre781834.d19cf9dfc633/nixexprs.tar.xz"
       },
       "original": {
         "type": "tarball",
diff --git a/pkgs/clan-cli/default.nix b/pkgs/clan-cli/default.nix
index 90aeb9870..042a23a90 100644
--- a/pkgs/clan-cli/default.nix
+++ b/pkgs/clan-cli/default.nix
@@ -166,14 +166,7 @@ pythonRuntime.pkgs.buildPythonApplication {
             buildInputs = [
               pkgs.bash
               pkgs.coreutils
-              # looks like Nix 2.26 fixes the profile creation race condition we were running into on Nix 2.24
-              # Switch this back to `pkgs.nix` when `pkgs.nix` is Nix 2.26+
-              (
-                assert
-                  lib.versionOlder pkgs.nix.version "2.26"
-                  && lib.versionAtLeast pkgs.nixVersions.latest.version "2.26";
-                pkgs.nixVersions.latest
-              )
+              pkgs.nix
             ];
             closureInfo = pkgs.closureInfo {
               rootPaths = [