--- a/testing/mozharness/mozharness/mozilla/testing/firefox_ui_tests.py
+++ b/testing/mozharness/mozharness/mozilla/testing/firefox_ui_tests.py
@@ -251,36 +251,36 @@ class FirefoxUITests(TestingMixin, VCSTo
 
         # Collect all pass-through harness options to the script
         cmd.extend(self.query_harness_args())
 
         # Translate deprecated --e10s flag
         if not self.config.get('e10s'):
             cmd.append('--disable-e10s')
 
-        # Set further environment settings
-        env = env or self.query_env()
-
         if self.symbols_url:
             cmd.extend(['--symbols-path', self.symbols_url])
 
-        if self.query_minidump_stackwalk():
-            env['MINIDUMP_STACKWALK'] = self.minidump_stackwalk_path
-
         if self.config.get('tag'):
             cmd.extend(['--tag', self.config['tag']])
 
         parser = StructuredOutputParser(config=self.config,
                                         log_obj=self.log_obj,
                                         strict=False)
 
         # Add the default tests to run
         tests = [os.path.join(dirs['abs_fxui_dir'], 'tests', test) for test in self.default_tests]
         cmd.extend(tests)
 
+        # Set further environment settings
+        env = env or self.query_env()
+        env.update({'MINIDUMP_SAVE_PATH': dirs['abs_blob_upload_dir']})
+        if self.query_minidump_stackwalk():
+            env.update({'MINIDUMP_STACKWALK': self.minidump_stackwalk_path})
+
         return_code = self.run_command(cmd,
                                        cwd=dirs['abs_work_dir'],
                                        output_timeout=300,
                                        output_parser=parser,
                                        env=env)
 
         tbpl_status, log_level = parser.evaluate_parser(return_code)
         self.buildbot_status(tbpl_status, level=log_level)