--- a/process/factory.py
+++ b/process/factory.py
@@ -2542,18 +2542,17 @@ class ReleaseBuildFactory(MercurialBuild
                 workdir='%s/dist' % self.absMozillaObjDir,
                         haltOnFailure=True,
             ))
             self.UPLOAD_EXTRA_FILES.append(
                 '%s/%s' % (self.update_dir, partial_mar_name))
             if self.enableSigning and self.signingServers:
                 partial_mar_path = '%s/dist/%s/%s' % \
                     (self.absMozillaObjDir, self.update_dir, partial_mar_name)
-                cmd = '%s -f mar -f gpg "%s"' % (self.signing_command,
-                                                 partial_mar_path)
+                cmd = '%s -f mar "%s"' % (self.signing_command, partial_mar_path)
                 self.addStep(MockCommand(
                     name='sign_partial_mar',
                     description=['sign', 'partial', 'mar'],
                     command=['bash', '-c', WithProperties(cmd)],
                     env=updateEnv,
                     mock=self.use_mock,
                     target=self.mock_target,
                     workdir='.',