--- a/testing/mozharness/scripts/web_platform_tests.py
+++ b/testing/mozharness/scripts/web_platform_tests.py
@@ -93,17 +93,17 @@ class WebPlatformTest(TestingMixin, Merc
     def query_abs_dirs(self):
         if self.abs_dirs:
             return self.abs_dirs
         abs_dirs = super(WebPlatformTest, self).query_abs_dirs()
 
         dirs = {}
         dirs['abs_app_install_dir'] = os.path.join(abs_dirs['abs_work_dir'], 'application')
         dirs['abs_test_install_dir'] = os.path.join(abs_dirs['abs_work_dir'], 'tests')
-        dirs["abs_wpttest_dir"] = os.path.join(dirs['abs_test_install_dir'], "web-platform")
+        dirs['abs_wpttest_dir'] = os.path.join(abs_dirs['checkout'], 'testing', 'web-platform')
         dirs['abs_blob_upload_dir'] = os.path.join(abs_dirs['abs_work_dir'], 'blobber_upload_dir')
 
         abs_dirs.update(dirs)
         self.abs_dirs = abs_dirs
 
         return self.abs_dirs
 
     @PreScriptAction('create-virtualenv')
@@ -142,17 +142,17 @@ class WebPlatformTest(TestingMixin, Merc
             '--log-raw=-',
             '--log-raw=%s' % os.path.join(blob_upload_dir, 'wpt_raw.log'),
             '--log-errorsummary=%s' % os.path.join(blob_upload_dir,
                                                    'wpt_errorsummary.log'),
             '--binary=%s' % self.binary_path,
             '--symbols-path=%s' % self.query_symbols_url(),
             '--stackwalk-binary=%s' % self.query_minidump_stackwalk(),
             '--processes=1',
-            '--prefs-root=%s/prefs' % wpt_dir,
+            '--prefs-root=%s' % os.path.join(dirs['checkout'], 'testing', 'profiles'),
             '--config=%s/wptrunner.ini' % wpt_dir,
             '--ca-cert-path=%s/certs/cacert.pem' % wpt_dir,
             '--host-key-path=%s/certs/web-platform.test.key' % wpt_dir,
             '--host-cert-path=%s/certs/web-platform.test.pem' % wpt_dir,
             '--certutil-binary=%s/bin/certutil' % dirs['abs_test_install_dir'],
         ])
 
         for test_type in c.get("test_type", []):
@@ -192,17 +192,18 @@ class WebPlatformTest(TestingMixin, Merc
 
     def download_and_extract(self):
         super(WebPlatformTest, self).download_and_extract(
             extract_dirs=["bin/*",
                           "config/*",
                           "mozbase/*",
                           "marionette/*",
                           "tools/wptserve/*",
-                          "web-platform/*"],
+                          "web-platform/*",
+                          "mozinfo.json"],
             suite_categories=["web-platform"])
 
     def fetch_geckodriver(self):
         c = self.config
         dirs = self.query_abs_dirs()
 
         platform_name = self.platform_name()
 
@@ -240,17 +241,21 @@ class WebPlatformTest(TestingMixin, Merc
     def run_tests(self):
         dirs = self.query_abs_dirs()
         cmd = self._query_cmd()
 
         parser = StructuredOutputParser(config=self.config,
                                         log_obj=self.log_obj,
                                         log_compact=True)
 
-        env = {'MINIDUMP_SAVE_PATH': dirs['abs_blob_upload_dir']}
+        env = {
+            'MINIDUMP_SAVE_PATH': dirs['abs_blob_upload_dir'],
+            'MOZINFO_PATH': os.path.join(dirs['abs_test_install_dir'],
+                                         'mozinfo.json'),
+        }
 
         if self.config['allow_software_gl_layers']:
             env['MOZ_LAYERS_ALLOW_SOFTWARE_GL'] = '1'
 
         env = self.query_env(partial_env=env, log_level=INFO)
 
         return_code = self.run_command(cmd,
                                        cwd=dirs['abs_work_dir'],