diff --git a/components/utilities/ymodem/ymodem.c b/components/utilities/ymodem/ymodem.c
index f5ebeab83..3af152802 100644
--- a/components/utilities/ymodem/ymodem.c
+++ b/components/utilities/ymodem/ymodem.c
@@ -197,7 +197,7 @@ static rt_err_t _rym_do_trans(struct rym_ctx *ctx)
     {
         rt_err_t err;
         enum rym_code code;
-        rt_size_t data_sz;
+        rt_size_t data_sz, i;
 
         code = _rym_read_code(ctx,
                 RYM_WAIT_PKG_TICK);
@@ -223,8 +223,9 @@ static rt_err_t _rym_do_trans(struct rym_ctx *ctx)
         {
         case RYM_CODE_CAN:
             /* the spec require multiple CAN */
-            _rym_putchar(ctx, RYM_CODE_CAN);
-            _rym_putchar(ctx, RYM_CODE_CAN);
+            for (i = 0; i < RYM_END_SESSION_SEND_CAN_NUM; i++) {
+                _rym_putchar(ctx, RYM_CODE_CAN);
+            }
             return -RYM_ERR_CAN;
         case RYM_CODE_ACK:
             _rym_putchar(ctx, RYM_CODE_ACK);
diff --git a/components/utilities/ymodem/ymodem.h b/components/utilities/ymodem/ymodem.h
index 43ee6f5c1..d82e76d93 100644
--- a/components/utilities/ymodem/ymodem.h
+++ b/components/utilities/ymodem/ymodem.h
@@ -55,6 +55,9 @@ enum rym_code {
 #define RYM_CHD_INTV_TICK (RT_TICK_PER_SECOND * 3)
 #endif
 
+/* how many CAN be sent when user active end the session. */
+#define RYM_END_SESSION_SEND_CAN_NUM  0x07
+
 enum rym_stage {
     RYM_STAGE_NONE,
     /* set when C is send */
@@ -129,7 +132,7 @@ struct rym_ctx
  * second.
  */
 rt_err_t rym_recv_on_device(struct rym_ctx *ctx, rt_device_t dev,
-        rym_callback on_begin, rym_callback on_data, rym_callback on_end,
-        int handshake_timeout);
+        rt_uint16_t oflag, rym_callback on_begin, rym_callback on_data,
+        rym_callback on_end, int handshake_timeout);
 
 #endif