--- a/toolkit/components/reader/ReaderMode.jsm
+++ b/toolkit/components/reader/ReaderMode.jsm
@@ -233,20 +233,20 @@ this.ReaderMode = {
             }
           }
         }
         let responseURL = xhr.responseURL;
         let givenURL = url;
         // Convert these to real URIs to make sure the escaping (or lack
         // thereof) is identical:
         try {
-          responseURL = Services.io.newURI(responseURL, null, null).spec;
+          responseURL = Services.io.newURI(responseURL, null, null).specIgnoringRef;
         } catch (ex) { /* Ignore errors - we'll use what we had before */ }
         try {
-          givenURL = Services.io.newURI(givenURL, null, null).spec;
+          givenURL = Services.io.newURI(givenURL, null, null).specIgnoringRef;
         } catch (ex) { /* Ignore errors - we'll use what we had before */ }
 
         if (responseURL != givenURL) {
           // We were redirected without a meta refresh tag.
           // Force redirect to the correct place:
           reject({newURL: xhr.responseURL});
           return;
         }