diff --git a/pkgs/development/python-modules/fx2/default.nix b/pkgs/development/python-modules/fx2/default.nix
index bcc7a4b5c988..e82679443562 100644
--- a/pkgs/development/python-modules/fx2/default.nix
+++ b/pkgs/development/python-modules/fx2/default.nix
@@ -14,7 +14,7 @@ buildPythonPackage rec {
   src = fetchFromGitHub {
     owner = "whitequark";
     repo = "libfx2";
-    rev = version;
+    rev = "v${version}";
     sha256 = "sha256-Uk+K7ym92JX4fC3PyTNxd0UvBzoNZmtbscBYjSWChuk=";
   };