diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 156e2a0242..55987f329e 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -2034,9 +2034,9 @@ static int mmc_select_hs400(struct mmc *mmc)
 	mmc_set_clock(mmc, mmc->tran_speed, false);
 
 	/* execute tuning if needed */
-	mmc->hs400_tuning = 1;
+	mmc->hs400_tuning = true;
 	err = mmc_execute_tuning(mmc, MMC_CMD_SEND_TUNING_BLOCK_HS200);
-	mmc->hs400_tuning = 0;
+	mmc->hs400_tuning = false;
 	if (err) {
 		debug("tuning failed\n");
 		return err;
diff --git a/include/mmc.h b/include/mmc.h
index 8df14130ed..a4584f8472 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -736,7 +736,7 @@ struct mmc {
 				  * accessing the boot partitions
 				  */
 	u32 quirks;
-	u8 hs400_tuning;
+	bool hs400_tuning:1;
 
 	enum bus_mode user_speed_mode; /* input speed mode from user */
 };