diff --git a/tools/ci/check_stability.py b/tools/ci/check_stability.py
index 684f7a518940c4..2b32eb50c0f624 100644
--- a/tools/ci/check_stability.py
+++ b/tools/ci/check_stability.py
@@ -266,8 +266,7 @@ def run(venv, wpt_args, **kwargs):
         do_delayed_imports()
 
         wpt_kwargs["prompt"] = False
-        wpt_kwargs["install_browser"] = True
-        wpt_kwargs["install"] = wpt_kwargs["product"].split(":")[0] == "firefox"
+        wpt_kwargs["install_browser"] = wpt_kwargs["product"].split(":")[0] == "firefox"
 
         wpt_kwargs["pause_after_test"] = False
         wpt_kwargs["verify_log_full"] = False