diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 1b0adf5c2376017b20417167c83ff571a3af1dfd..7188f0fb2e050bf69daf66b752ad458f25a9ac91 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -2595,6 +2595,11 @@ static int btusb_setup_qca_download_fw(struct hci_dev *hdev,
 	sent += size;
 	count -= size;
 
+	/* ep2 need time to switch from function acl to function dfu,
+	 * so we add 20ms delay here.
+	 */
+	msleep(20);
+
 	while (count) {
 		size = min_t(size_t, count, QCA_DFU_PACKET_LEN);