diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 57a8bd3..4466f5d 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1282,6 +1282,10 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
 
 	mmc_set_bus_speed(card);
 
+	/* Prepare tuning for HS400 mode. */
+	if (host->ops->prepare_hs400_tuning)
+		host->ops->prepare_hs400_tuning(host, &host->ios);
+
 	return 0;
 
 out_err: