--- a/testing/firefox-ui/harness/firefox_ui_harness/testcases.py
+++ b/testing/firefox-ui/harness/firefox_ui_harness/testcases.py
@@ -58,21 +58,16 @@ class UpdateTestCase(PuppeteerMixin, Mar
         if self.update_mar_channels:
             self.software_update.mar_channels.add_channels(self.update_mar_channels)
 
         # Ensure that there exists no already partially downloaded update
         self.remove_downloaded_update()
 
         self.set_preferences_defaults()
 
-        # Bug 1142805 - Until we don't modify the channel-prefs.js and update-settings.ini
-        # files before Firefox gets started, a restart of Firefox is necessary to
-        # accept the new update channel.
-        self.restart()
-
         # Dictionary which holds the information for each update
         self.updates = [{
             'build_pre': self.software_update.build_info,
             'build_post': None,
             'fallback': is_fallback,
             'patch': {},
             'success': False,
         }]