diff --git a/src/http/modules/ngx_http_flv_module.c b/src/http/modules/ngx_http_flv_module.c
index a7ee53cbb..ef2bff433 100644
--- a/src/http/modules/ngx_http_flv_module.c
+++ b/src/http/modules/ngx_http_flv_module.c
@@ -235,6 +235,7 @@ ngx_http_flv_handler(ngx_http_request_t *r)
     b->in_file = b->file_last ? 1 : 0;
     b->last_buf = (r == r->main) ? 1 : 0;
     b->last_in_chain = 1;
+    b->sync = (b->last_buf || b->in_file) ? 0 : 1;
 
     b->file->fd = of.fd;
     b->file->name = path;
diff --git a/src/http/modules/ngx_http_gzip_static_module.c b/src/http/modules/ngx_http_gzip_static_module.c
index 0ab14636e..91b38d17b 100644
--- a/src/http/modules/ngx_http_gzip_static_module.c
+++ b/src/http/modules/ngx_http_gzip_static_module.c
@@ -273,6 +273,7 @@ ngx_http_gzip_static_handler(ngx_http_request_t *r)
     b->in_file = b->file_last ? 1 : 0;
     b->last_buf = (r == r->main) ? 1 : 0;
     b->last_in_chain = 1;
+    b->sync = (b->last_buf || b->in_file) ? 0 : 1;
 
     b->file->fd = of.fd;
     b->file->name = path;
diff --git a/src/http/modules/ngx_http_mp4_module.c b/src/http/modules/ngx_http_mp4_module.c
index 75a7315f9..03175dea2 100644
--- a/src/http/modules/ngx_http_mp4_module.c
+++ b/src/http/modules/ngx_http_mp4_module.c
@@ -714,6 +714,7 @@ ngx_http_mp4_handler(ngx_http_request_t *r)
     b->in_file = b->file_last ? 1 : 0;
     b->last_buf = (r == r->main) ? 1 : 0;
     b->last_in_chain = 1;
+    b->sync = (b->last_buf || b->in_file) ? 0 : 1;
 
     b->file->fd = of.fd;
     b->file->name = path;
diff --git a/src/http/modules/ngx_http_static_module.c b/src/http/modules/ngx_http_static_module.c
index 3e65edfdb..8b0bb1478 100644
--- a/src/http/modules/ngx_http_static_module.c
+++ b/src/http/modules/ngx_http_static_module.c
@@ -238,10 +238,6 @@ ngx_http_static_handler(ngx_http_request_t *r)
         return NGX_HTTP_INTERNAL_SERVER_ERROR;
     }
 
-    if (r != r->main && of.size == 0) {
-        return ngx_http_send_header(r);
-    }
-
     r->allow_ranges = 1;
 
     /* we need to allocate all before the header would be sent */
@@ -268,6 +264,7 @@ ngx_http_static_handler(ngx_http_request_t *r)
     b->in_file = b->file_last ? 1 : 0;
     b->last_buf = (r == r->main) ? 1 : 0;
     b->last_in_chain = 1;
+    b->sync = (b->last_buf || b->in_file) ? 0 : 1;
 
     b->file->fd = of.fd;
     b->file->name = path;
diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index 6b1cb4fa4..2140e0627 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -1803,10 +1803,6 @@ ngx_http_send_response(ngx_http_request_t *r, ngx_uint_t status,
         }
     }
 
-    if (r != r->main && val.len == 0) {
-        return ngx_http_send_header(r);
-    }
-
     b = ngx_calloc_buf(r->pool);
     if (b == NULL) {
         return NGX_HTTP_INTERNAL_SERVER_ERROR;
@@ -1817,6 +1813,7 @@ ngx_http_send_response(ngx_http_request_t *r, ngx_uint_t status,
     b->memory = val.len ? 1 : 0;
     b->last_buf = (r == r->main) ? 1 : 0;
     b->last_in_chain = 1;
+    b->sync = (b->last_buf || b->memory) ? 0 : 1;
 
     out.buf = b;
     out.next = NULL;
diff --git a/src/http/ngx_http_file_cache.c b/src/http/ngx_http_file_cache.c
index 8db24f103..aa5fd1917 100644
--- a/src/http/ngx_http_file_cache.c
+++ b/src/http/ngx_http_file_cache.c
@@ -1575,10 +1575,6 @@ ngx_http_cache_send(ngx_http_request_t *r)
     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                    "http file cache send: %s", c->file.name.data);
 
-    if (r != r->main && c->length - c->body_start == 0) {
-        return ngx_http_send_header(r);
-    }
-
     /* we need to allocate all before the header would be sent */
 
     b = ngx_calloc_buf(r->pool);
@@ -1603,6 +1599,7 @@ ngx_http_cache_send(ngx_http_request_t *r)
     b->in_file = (c->length - c->body_start) ? 1 : 0;
     b->last_buf = (r == r->main) ? 1 : 0;
     b->last_in_chain = 1;
+    b->sync = (b->last_buf || b->in_file) ? 0 : 1;
 
     b->file->fd = c->file.fd;
     b->file->name = c->file.name;