diff --git a/youtube_dl/downloader/fragment.py b/youtube_dl/downloader/fragment.py
index 6c02cfc98..0a3b1ece0 100644
--- a/youtube_dl/downloader/fragment.py
+++ b/youtube_dl/downloader/fragment.py
@@ -12,7 +12,6 @@
     encodeFilename,
     sanitize_open,
     sanitized_Request,
-    compat_str,
 )
 
 
diff --git a/youtube_dl/downloader/ism.py b/youtube_dl/downloader/ism.py
index 338820e71..5f6f9faef 100644
--- a/youtube_dl/downloader/ism.py
+++ b/youtube_dl/downloader/ism.py
@@ -232,10 +232,6 @@ def real_download(self, filename, info_dict):
             count = 0
             while count <= fragment_retries:
                 try:
-                    success = ctx['dl'].download(target_filename, {
-                        'url': segment_url,
-                        'http_headers': info_dict.get('http_headers'),
-                    })
                     success, frag_content = self._download_fragment(ctx, segment['url'], info_dict)
                     if not success:
                         return False