diff --git a/drivers/net/ethernet/mellanox/mlxsw/core_env.c b/drivers/net/ethernet/mellanox/mlxsw/core_env.c
index 3103fef43955..0c1306db7315 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/core_env.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core_env.c
@@ -660,8 +660,8 @@ static int mlxsw_env_module_has_temp_sensor(struct mlxsw_core *mlxsw_core,
 	u16 temp;
 	int err;
 
-	mlxsw_reg_mtbr_pack(mtbr_pl, MLXSW_REG_MTBR_BASE_MODULE_INDEX + module,
-			    1);
+	mlxsw_reg_mtbr_pack(mtbr_pl, 0,
+			    MLXSW_REG_MTBR_BASE_MODULE_INDEX + module, 1);
 	err = mlxsw_reg_query(mlxsw_core, MLXSW_REG(mtbr), mtbr_pl);
 	if (err)
 		return err;
diff --git a/drivers/net/ethernet/mellanox/mlxsw/core_hwmon.c b/drivers/net/ethernet/mellanox/mlxsw/core_hwmon.c
index 71ca3b561e62..f4bc711a16cf 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/core_hwmon.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core_hwmon.c
@@ -271,8 +271,8 @@ static ssize_t mlxsw_hwmon_module_temp_fault_show(struct device *dev,
 	int err;
 
 	module = mlxsw_hwmon_attr->type_index - mlxsw_hwmon->sensor_count;
-	mlxsw_reg_mtbr_pack(mtbr_pl, MLXSW_REG_MTBR_BASE_MODULE_INDEX + module,
-			    1);
+	mlxsw_reg_mtbr_pack(mtbr_pl, 0,
+			    MLXSW_REG_MTBR_BASE_MODULE_INDEX + module, 1);
 	err = mlxsw_reg_query(mlxsw_hwmon->core, MLXSW_REG(mtbr), mtbr_pl);
 	if (err) {
 		dev_err(dev, "Failed to query module temperature sensor\n");
diff --git a/drivers/net/ethernet/mellanox/mlxsw/reg.h b/drivers/net/ethernet/mellanox/mlxsw/reg.h
index 5de77d6e08ba..958df69cccb5 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/reg.h
+++ b/drivers/net/ethernet/mellanox/mlxsw/reg.h
@@ -9887,6 +9887,12 @@ MLXSW_ITEM_BIT_ARRAY(reg, mtwe, sensor_warning, 0x0, 0x10, 1);
 
 MLXSW_REG_DEFINE(mtbr, MLXSW_REG_MTBR_ID, MLXSW_REG_MTBR_LEN);
 
+/* reg_mtbr_slot_index
+ * Slot index (0: Main board).
+ * Access: Index
+ */
+MLXSW_ITEM32(reg, mtbr, slot_index, 0x00, 16, 4);
+
 /* reg_mtbr_base_sensor_index
  * Base sensors index to access (0 - ASIC sensor, 1-63 - ambient sensors,
  * 64-127 are mapped to the SFP+/QSFP modules sequentially).
@@ -9919,10 +9925,11 @@ MLXSW_ITEM32_INDEXED(reg, mtbr, rec_max_temp, MLXSW_REG_MTBR_BASE_LEN, 16,
 MLXSW_ITEM32_INDEXED(reg, mtbr, rec_temp, MLXSW_REG_MTBR_BASE_LEN, 0, 16,
 		     MLXSW_REG_MTBR_REC_LEN, 0x00, false);
 
-static inline void mlxsw_reg_mtbr_pack(char *payload, u16 base_sensor_index,
-				       u8 num_rec)
+static inline void mlxsw_reg_mtbr_pack(char *payload, u8 slot_index,
+				       u16 base_sensor_index, u8 num_rec)
 {
 	MLXSW_REG_ZERO(mtbr, payload);
+	mlxsw_reg_mtbr_slot_index_set(payload, slot_index);
 	mlxsw_reg_mtbr_base_sensor_index_set(payload, base_sensor_index);
 	mlxsw_reg_mtbr_num_rec_set(payload, num_rec);
 }