diff --git a/src/display/api.js b/src/display/api.js
index f842490474e17..e77cc6059a78c 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -515,6 +515,7 @@ const PDFDocumentLoadingTask = (function PDFDocumentLoadingTaskClosure() {
  * Abstract class to support range requests file loading.
  * @param {number} length
  * @param {Uint8Array} initialData
+ * @param {boolean} progressiveDone
  */
 class PDFDataRangeTransport {
   constructor(length, initialData, progressiveDone = false) {
@@ -551,10 +552,10 @@ class PDFDataRangeTransport {
     }
   }
 
-  onDataProgress(loaded) {
+  onDataProgress(loaded, total) {
     this._readyCapability.promise.then(() => {
       for (const listener of this._progressListeners) {
-        listener(loaded);
+        listener(loaded, total);
       }
     });
   }
diff --git a/src/display/transport_stream.js b/src/display/transport_stream.js
index e734b112cca12..f21c070dff283 100644
--- a/src/display/transport_stream.js
+++ b/src/display/transport_stream.js
@@ -41,8 +41,8 @@ var PDFDataTransportStream = (function PDFDataTransportStreamClosure() {
       this._onReceiveData({ begin, chunk, });
     });
 
-    this._pdfDataRangeTransport.addProgressListener((loaded) => {
-      this._onProgress({ loaded, });
+    this._pdfDataRangeTransport.addProgressListener((loaded, total) => {
+      this._onProgress({ loaded, total, });
     });
 
     this._pdfDataRangeTransport.addProgressiveReadListener((chunk) => {
@@ -77,13 +77,18 @@ var PDFDataTransportStream = (function PDFDataTransportStreamClosure() {
     },
 
     _onProgress: function PDFDataTransportStream_onDataProgress(evt) {
-       if (this._rangeReaders.length > 0) {
+       if (evt.total === undefined && this._rangeReaders.length > 0) {
          // Reporting to first range reader.
          var firstReader = this._rangeReaders[0];
          if (firstReader.onProgress) {
            firstReader.onProgress({ loaded: evt.loaded, });
+           return;
          }
        }
+       let fullReader = this._fullRequestReader;
+       if (fullReader && fullReader.onProgress) {
+         fullReader.onProgress({ loaded: evt.loaded, total: evt.total, });
+       }
     },
 
     _onProgressiveDone() {
diff --git a/web/firefoxcom.js b/web/firefoxcom.js
index bea171d1a1f01..22e044801ffa5 100644
--- a/web/firefoxcom.js
+++ b/web/firefoxcom.js
@@ -269,6 +269,10 @@ PDFViewerApplication.externalServices = {
           break;
         case 'progressiveRead':
           pdfDataRangeTransport.onDataProgressiveRead(args.chunk);
+
+          // Don't forget to report loading progress as well, since otherwise
+          // the loadingBar won't update when `disableRange=true` is set.
+          pdfDataRangeTransport.onDataProgress(args.loaded, args.total);
           break;
         case 'progressiveDone':
           if (pdfDataRangeTransport) {