diff --git a/flake.lock b/flake.lock
index bb0a2fca..7c9c59b3 100644
--- a/flake.lock
+++ b/flake.lock
@@ -2,11 +2,11 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1677080879,
-        "narHash": "sha256-0SjW4/d3Rkw6C7hHZ5lxT4r6Pw9vzQb6Il6zYWwe2Bo=",
+        "lastModified": 1678724065,
+        "narHash": "sha256-MjeRjunqfGTBGU401nxIjs7PC9PZZ1FBCZp/bRB3C2M=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "f5dad40450d272a1ea2413f4a67ac08760649e89",
+        "rev": "b8afc8489dc96f29f69bec50fdc51e27883f89c1",
         "type": "github"
       },
       "original": {
diff --git a/overlay.nix b/overlay.nix
index 61b9c15b..68866c0b 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -22,7 +22,7 @@ let
       # Add additional compiler flags
       extraAttrs = {
         mkDerivation = args: (stdenv.mkDerivation args).overrideAttrs (old: {
-          NIX_CFLAGS_COMPILE = toString (old.NIX_CFLAGS_COMPILE or "")
+          env.NIX_CFLAGS_COMPILE = toString (old.env.NIX_CFLAGS_COMPILE or "")
             + " -march=${arch} -mtune=${arch} " + extraCflags;
         });
       };