diff --git a/ci-tools/update-nixpkgs b/ci-tools/update-nixpkgs
index e8ce8fbdd6d8204b4460aec2af0df6b82c0032ed..8a4e6eea2ff316c2c1661a9c1ad224ff9d874a6a 100755
--- a/ci-tools/update-nixpkgs
+++ b/ci-tools/update-nixpkgs
@@ -10,7 +10,7 @@ nix-build -A morph -o result-before
 
 git checkout "${TARGET_BRANCH}" || git checkout -b "${TARGET_BRANCH}"
 
-update-nixpkgs
+./update-nixpkgs
 nix-build -A morph -o result-after
 diff=$(nix --extra-experimental-features nix-command store diff-closures ./result-before/ ./result-after/)