diff --git a/src/calibre/customize/builtins.py b/src/calibre/customize/builtins.py
index 74102f4a27..341a7fa37d 100644
--- a/src/calibre/customize/builtins.py
+++ b/src/calibre/customize/builtins.py
@@ -356,7 +356,7 @@ from calibre.devices.prs505.driver import PRS505
 from calibre.devices.prs700.driver import PRS700
 
 
-plugins = []
+plugins = [HTML2ZIP]
 plugins += [
     ComicInput,
     EPUBInput,
diff --git a/src/calibre/gui2/dialogs/config.py b/src/calibre/gui2/dialogs/config.py
index 70237548d5..2b5e9d4cf2 100644
--- a/src/calibre/gui2/dialogs/config.py
+++ b/src/calibre/gui2/dialogs/config.py
@@ -153,7 +153,7 @@ class PluginModel(QAbstractItemModel):
     def flags(self, index):
         if not index.isValid():
             return 0
-        if index.internalId() == -1:
+        if index.internalId() == 0:
             return Qt.ItemIsEnabled
         flags = Qt.ItemIsSelectable | Qt.ItemIsEnabled
         return flags
@@ -161,7 +161,7 @@ class PluginModel(QAbstractItemModel):
     def data(self, index, role):
         if not index.isValid():
             return NONE
-        if index.internalId() == -1:
+        if index.internalId() == 0:
             if role == Qt.DisplayRole:
                 category = self.categories[index.row()]
                 return QVariant(category + _(' plugins'))