diff --git a/monitor/bt.h b/monitor/bt.h
index ec62864..1fbb40e 100644
--- a/monitor/bt.h
+++ b/monitor/bt.h
@@ -2359,8 +2359,8 @@ struct bt_hci_rsp_le_read_dev_periodic_adv_list_size {
 #define BT_HCI_CMD_LE_READ_TX_POWER		0x204b
 struct bt_hci_rsp_le_read_tx_power {
 	uint8_t  status;
-	uint8_t  min_tx_power;
-	uint8_t  max_tx_power;
+	int8_t  min_tx_power;
+	int8_t  max_tx_power;
 } __attribute__ ((packed));
 
 #define BT_HCI_CMD_LE_READ_RF_PATH_COMPENSATION		0x204c