diff --git a/src/public/speedtest_worker.js b/src/public/speedtest_worker.js
index 406c054..576cd68 100644
--- a/src/public/speedtest_worker.js
+++ b/src/public/speedtest_worker.js
@@ -122,14 +122,10 @@ this.addEventListener("message", function(e) {
 				if (typeof settings[key] !== "undefined") settings[key] = s[key];
 				else twarn("Unknown setting ignored: " + key);
 			}
+			var ua = navigator.userAgent;
 			// quirks for specific browsers. apply only if not overridden. more may be added in future releases
 			if (settings.enable_quirks || (typeof s.enable_quirks !== "undefined" && s.enable_quirks)) {
-				var ua = navigator.userAgent;
 				if (/Firefox.(\d+\.\d+)/i.test(ua)) {
-					if (typeof s.xhr_ulMultistream === "undefined") {
-						// ff more precise with 1 upload stream
-						settings.xhr_ulMultistream = 1;
-					}
 					if (typeof s.ping_allowPerformanceApi === "undefined") {
 						// ff performance API sucks
 						settings.ping_allowPerformanceApi = false;