diff --git a/src/calibre/gui2/viewer/ui.py b/src/calibre/gui2/viewer/ui.py
index edabdabd2a..67eae34ed4 100644
--- a/src/calibre/gui2/viewer/ui.py
+++ b/src/calibre/gui2/viewer/ui.py
@@ -403,19 +403,22 @@ class EbookViewer(MainWindow):
         self.load_book_data()
         self.update_window_title()
         initial_cfi = self.initial_cfi_for_current_book()
-        initial_toc_node = initial_bookpos = None
+        initial_position = {'type': 'cfi', 'data': initial_cfi} if initial_cfi else None
         if open_at:
             if open_at.startswith('toc:'):
                 initial_toc_node = self.toc_model.node_id_for_text(open_at[len('toc:'):])
+                initial_position = {'type': 'toc', 'data': initial_toc_node}
             elif open_at.startswith('toc-href:'):
                 initial_toc_node = self.toc_model.node_id_for_href(open_at[len('toc-href:'):], exact=True)
+                initial_position = {'type': 'toc', 'data': initial_toc_node}
             elif open_at.startswith('toc-href-contains:'):
                 initial_toc_node = self.toc_model.node_id_for_href(open_at[len('toc-href-contains:'):], exact=False)
+                initial_position = {'type': 'toc', 'data': initial_toc_node}
             elif open_at.startswith('epubcfi(/'):
-                initial_cfi = open_at
+                initial_position = {'type': 'cfi', 'data': open_at}
             elif is_float(open_at):
-                initial_bookpos = float(open_at)
-        self.web_view.start_book_load(initial_cfi=initial_cfi, initial_toc_node=initial_toc_node, initial_bookpos=initial_bookpos)
+                initial_position = {'type': 'bookpos', 'data': float(open_at)}
+        self.web_view.start_book_load(initial_position=initial_position)
 
     def load_book_data(self):
         self.load_book_annotations()
diff --git a/src/calibre/gui2/viewer/web_view.py b/src/calibre/gui2/viewer/web_view.py
index 832251772d..acf0a137c8 100644
--- a/src/calibre/gui2/viewer/web_view.py
+++ b/src/calibre/gui2/viewer/web_view.py
@@ -544,9 +544,9 @@ class WebView(RestartingWebEngineView):
         for func, args in iteritems(self.pending_bridge_ready_actions):
             getattr(self.bridge, func)(*args)
 
-    def start_book_load(self, initial_cfi=None, initial_toc_node=None, initial_bookpos=None):
+    def start_book_load(self, initial_position=None):
         key = (set_book_path.path,)
-        self.execute_when_ready('start_book_load', key, initial_cfi, initial_toc_node, initial_bookpos, set_book_path.pathtoebook)
+        self.execute_when_ready('start_book_load', key, initial_position, set_book_path.pathtoebook)
 
     def execute_when_ready(self, action, *args):
         if self.bridge.ready:
diff --git a/src/pyj/read_book/view.pyj b/src/pyj/read_book/view.pyj
index e11bc66d33..096c65bb05 100644
--- a/src/pyj/read_book/view.pyj
+++ b/src/pyj/read_book/view.pyj
@@ -616,7 +616,7 @@ class View:
                 cfi =  '/' + rest
         return name, cfi
 
-    def display_book(self, book, initial_cfi, initial_toc_node, initial_bookpos):
+    def display_book(self, book, initial_position):
         self.hide_overlays()
         self.iframe.focus()
         is_current_book = self.book and self.book.key == book.key
@@ -636,8 +636,8 @@ class View:
         unkey = username_key(get_interface_data().username)
         name = book.manifest.spine[0]
         cfi = None
-        if initial_cfi and initial_cfi.startswith('epubcfi(/'):
-            cfi = initial_cfi
+        if initial_position and initial_position.type is 'cfi' and initial_position.data.startswith('epubcfi(/'):
+            cfi = initial_position.data
         else:
             q = parse_url_params()
             if q.bookpos and q.bookpos.startswith('epubcfi(/'):
@@ -649,11 +649,12 @@ class View:
             name = cfiname
             pos.type, pos.cfi = 'cfi', internal_cfi
         navigated = False
-        if jstype(initial_toc_node) is 'number':
-            navigated = self.goto_toc_node(initial_toc_node)
-        if not navigated and jstype(initial_bookpos) is 'number':
-            navigated = True
-            self.goto_book_position(initial_bookpos)
+        if initial_position:
+            if initial_position.type is 'toc':
+                navigated = self.goto_toc_node(initial_position.data)
+            elif initial_position.type is 'bookpos':
+                navigated = True
+                self.goto_book_position(initial_position.data)
         if navigated:
             self.hide_loading()
         else:
diff --git a/src/pyj/viewer-main.pyj b/src/pyj/viewer-main.pyj
index 0af0db74f6..86ab98f67c 100644
--- a/src/pyj/viewer-main.pyj
+++ b/src/pyj/viewer-main.pyj
@@ -138,7 +138,7 @@ def show_error(title, msg, details):
     to_python.show_error(title, msg, details)
 
 
-def manifest_received(key, initial_cfi, initial_toc_node, initial_bookpos, pathtoebook, end_type, xhr, ev):
+def manifest_received(key, initial_position, pathtoebook, end_type, xhr, ev):
     nonlocal book
     end_type = workaround_qt_bug(xhr, end_type)
     if end_type is 'load':
@@ -151,7 +151,7 @@ def manifest_received(key, initial_cfi, initial_toc_node, initial_bookpos, patht
         book.is_complete = True
         v'delete book.manifest["metadata"]'
         v'delete book.manifest["last_read_positions"]'
-        view.display_book(book, initial_cfi, initial_toc_node, initial_bookpos)
+        view.display_book(book, initial_position)
     else:
         show_error(_('Could not open book'), _(
             'Failed to load book manifest, click "Show details" for more info'),
@@ -241,8 +241,8 @@ def show_home_page():
 
 
 @from_python
-def start_book_load(key, initial_cfi, initial_toc_node, initial_bookpos, pathtoebook):
-    xhr = ajax('manifest', manifest_received.bind(None, key, initial_cfi, initial_toc_node, initial_bookpos, pathtoebook), ok_code=0)
+def start_book_load(key, initial_position, pathtoebook):
+    xhr = ajax('manifest', manifest_received.bind(None, key, initial_position, pathtoebook), ok_code=0)
     xhr.responseType = 'json'
     xhr.send()