diff --git a/flake.lock b/flake.lock
index 1930cc3d..b05fe3d9 100644
--- a/flake.lock
+++ b/flake.lock
@@ -2,17 +2,17 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1637328665,
-        "narHash": "sha256-z6ufVwquLM0IiNZxd5oT1M33Lv0aB3WICpk8ZKwpxjw=",
+        "lastModified": 1638887115,
+        "narHash": "sha256-emjtIeqyJ84Eb3X7APJruTrwcfnHQKs55XGljj62prs=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "0f4b4b85d959200f52c16bbb74036994e7db5f74",
+        "rev": "1bd4bbd49bef217a3d1adea43498270d6e779d65",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
+        "ref": "nixos-21.11",
         "repo": "nixpkgs",
-        "rev": "0f4b4b85d959200f52c16bbb74036994e7db5f74",
         "type": "github"
       }
     },
diff --git a/flake.nix b/flake.nix
index f7be349f..60d18c67 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,12 +1,21 @@
 {
   description = "The third-generation ARTIQ compiler";
 
-  inputs.nixpkgs.url = github:NixOS/nixpkgs/0f4b4b85d959200f52c16bbb74036994e7db5f74;
+  inputs.nixpkgs.url = github:NixOS/nixpkgs/nixos-21.11;
 
   outputs = { self, nixpkgs }:
     let
       pkgs = import nixpkgs { system = "x86_64-linux"; };
-      pkgs-mingw = import nixpkgs { system = "x86_64-linux"; crossSystem = { config = "x86_64-w64-mingw32"; libc = "msvcrt"; }; };
+      pkgs-mingw = import nixpkgs {
+        system = "x86_64-linux";
+        crossSystem = { config = "x86_64-w64-mingw32"; libc = "msvcrt"; };
+        # work around https://github.com/NixOS/nixpkgs/issues/149593
+        overlays = [
+          (self: super: {
+            openssh = super.openssh.overrideAttrs(oa: { doCheck = false; });
+          })
+        ];
+      };
       cargoSha256 = "sha256-otKLhr58HYMjVXAof6AdObNpggPnvK6qOl7I+4LWIP8=";
       msys2-python-tar = pkgs.fetchurl {
         url = "https://mirror.msys2.org/mingw/mingw64/mingw-w64-x86_64-python-3.9.7-4-any.pkg.tar.zst";