diff --git a/pungi_utils/orchestrator.py b/pungi_utils/orchestrator.py
index d18019de..b94ddc46 100644
--- a/pungi_utils/orchestrator.py
+++ b/pungi_utils/orchestrator.py
@@ -106,7 +106,9 @@ class ComposePart(object):
             self.status = Status.READY
 
     def setup_start(self, global_config, parts):
-        substitutions = dict((name, p.path) for name, p in parts.items() if p.is_finished())
+        substitutions = dict(
+            ("part-%s" % name, p.path) for name, p in parts.items() if p.is_finished()
+        )
         substitutions["configdir"] = global_config.config_dir
 
         config = kobo.conf.PyConfigParser()
diff --git a/tests/test_orchestrator.py b/tests/test_orchestrator.py
index 35fe1ddc..79d5f293 100644
--- a/tests/test_orchestrator.py
+++ b/tests/test_orchestrator.py
@@ -184,7 +184,7 @@ class TestComposePart(PungiTestCase):
         self.assertEqual(part.log_file, pth("tgt", "logs", "test.log"))
         self.assertEqual(
             ficf.call_args_list,
-            [mock.call("foo.conf", {"base": "/base", "configdir": pth("cfg")})],
+            [mock.call("foo.conf", {"part-base": "/base", "configdir": pth("cfg")})],
         )
         self.assertEqual(
             gcd.call_args_list,