diff --git a/drivers/rtc/rtc-nct3018y.c b/drivers/rtc/rtc-nct3018y.c
index c5d7cd8862ab0f..d1bd079794e7b1 100644
--- a/drivers/rtc/rtc-nct3018y.c
+++ b/drivers/rtc/rtc-nct3018y.c
@@ -670,7 +670,7 @@ static int nct3018y_probe(struct i2c_client *client,
 	} else {
 		nct3018y->part_num &= 0x03; /* Part number is corresponding to bit 0 and 1 */
 		if (nct3018y->part_num == NCT3018Y_REG_PART_NCT3018Y) {
-			flags = NCT3018Y_BIT_HF;
+			flags |= NCT3018Y_BIT_HF;
 			err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
 			if (err < 0) {
 				dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_CTRL.\n");