diff --git a/include/haproxy/h1.h b/include/haproxy/h1.h
index 7ebd9c84b..1891c81ce 100644
--- a/include/haproxy/h1.h
+++ b/include/haproxy/h1.h
@@ -99,6 +99,14 @@ enum h1m_state {
 #define H1_MF_TE_CHUNKED        0x00010000 // T-E "chunked"
 #define H1_MF_TE_OTHER          0x00020000 // T-E other than supported ones found (only "chunked" is supported for now)
 
+/* Mask to use to reset H1M flags when we restart headers parsing.
+ *
+ * WARNING: Don't forget to update it if a new flag must be preserved when
+ *          headers parsing is restarted.
+ */
+#define H1_MF_RESTART_MASK    (H1_MF_RESP|H1_MF_TOLOWER|H1_MF_NO_PHDR|H1_MF_HDRS_ONLY| \
+			       H1_MF_CLEAN_CONN_HDR|H1_MF_METH_CONNECT|H1_MF_METH_HEAD)
+
 /* Note: for a connection to be persistent, we need this for the request :
  *   - one of CLEN or CHNK
  *   - version 1.0 and KAL and not CLO
diff --git a/src/h1.c b/src/h1.c
index 99b9c2993..dd208f323 100644
--- a/src/h1.c
+++ b/src/h1.c
@@ -1040,7 +1040,7 @@ int h1_headers_to_hdr_list(char *start, const char *stop,
 	return -2;
 
  restart:
-	h1m->flags &= ~(H1_MF_VER_11|H1_MF_CLEN|H1_MF_XFER_ENC|H1_MF_CHNK|H1_MF_CONN_KAL|H1_MF_CONN_CLO|H1_MF_CONN_UPG);
+	h1m->flags &= H1_MF_RESTART_MASK;
 	h1m->curr_len = h1m->body_len = h1m->next  = 0;
 	if (h1m->flags & H1_MF_RESP)
 		h1m->state = H1_MSG_RPBEFORE;