diff --git a/pkgs/development/python-modules/sat-tmp/default.nix b/pkgs/development/python-modules/sat-tmp/default.nix
index 569a8d042cf1..7ac981cfda2b 100644
--- a/pkgs/development/python-modules/sat-tmp/default.nix
+++ b/pkgs/development/python-modules/sat-tmp/default.nix
@@ -31,6 +31,9 @@ buildPythonPackage rec {
   # no pytest tests exist
   doCheck = false;
 
+  # Default-added updateScript doesn't handle Mercurial sources
+  passthru.updateScript = null;
+
   meta = {
     description = "Libervia temporary third party patches";
     longDescription = ''