Update 'README.md'

README.md

@@ -20,6 +20,22 @@ On the other hand, it tries to avoid all the automatic connections even though s
 
 It has also some changes in order to improve fingerprinting like canvas.poisondata and others.
 
+## Known problems
+
+`Some breakage?`
+
+Try changing "network.http.referer.XOriginPolicy" from 2 to 1
+
+`Performance loss?`
+
+Change these strings from false to true:
+
+javascript.options.ion
+
+javascript.options.baselinejit
+
+javascript.options.native_regexp
+
 ## Thanks:
 
 * [Arkenfox user.js](https://github.com/arkenfox/user.js)