diff --git a/panda/src/downloader/httpChannel.cxx b/panda/src/downloader/httpChannel.cxx
index 0dd0cef14c..af44780713 100644
--- a/panda/src/downloader/httpChannel.cxx
+++ b/panda/src/downloader/httpChannel.cxx
@@ -170,7 +170,7 @@ will_close_connection() const {
 //               once for a particular HTTPChannel.
 ////////////////////////////////////////////////////////////////////
 istream *HTTPChannel::
-open_read_file() const {
+open_read_file(bool auto_unwrap) const {
   return ((HTTPChannel *)this)->read_body();
 }
 
diff --git a/panda/src/downloader/httpChannel.h b/panda/src/downloader/httpChannel.h
index 41b72a2f1b..6c907e7a48 100644
--- a/panda/src/downloader/httpChannel.h
+++ b/panda/src/downloader/httpChannel.h
@@ -72,7 +72,7 @@ public:
   virtual Filename get_filename() const;
 
   virtual bool is_regular_file() const;
-  virtual istream *open_read_file() const;
+  virtual istream *open_read_file(bool auto_unwrap) const;
   void close_read_file(istream *stream) const;
 
   bool will_close_connection() const;