diff --git a/libs/libc/stream/lib_blkoutstream.c b/libs/libc/stream/lib_blkoutstream.c
index 0126f47cb3b..10533b97688 100644
--- a/libs/libc/stream/lib_blkoutstream.c
+++ b/libs/libc/stream/lib_blkoutstream.c
@@ -174,6 +174,7 @@ void lib_blkoutstream_close(FAR struct lib_blkoutstream_s *stream)
 
       if (stream->cache != NULL)
         {
+          blkoutstream_flush(&stream->common);
           lib_free(stream->cache);
           stream->cache = NULL;
         }
diff --git a/libs/libc/stream/lib_mtdoutstream.c b/libs/libc/stream/lib_mtdoutstream.c
index d0765bb5df2..a726f317eba 100644
--- a/libs/libc/stream/lib_mtdoutstream.c
+++ b/libs/libc/stream/lib_mtdoutstream.c
@@ -240,6 +240,7 @@ void lib_mtdoutstream_close(FAR struct lib_mtdoutstream_s *stream)
 
       if (stream->cache != NULL)
         {
+          mtdoutstream_flush(&stream->common);
           lib_free(stream->cache);
           stream->cache = NULL;
         }