diff --git a/prj.conf b/prj.conf
index bd0fc6e..e93626c 100644
--- a/prj.conf
+++ b/prj.conf
@@ -70,11 +70,11 @@ CONFIG_BT_BUF_ACL_TX_SIZE=251
 CONFIG_BT_BUF_ACL_RX_SIZE=251
 
 # Connection parameters
-# Preferred minimum connection interval: 12 x 1.25ms = 15ms.
-CONFIG_BT_PERIPHERAL_PREF_MIN_INT=12
-# Preferred maximum connection interval: 12 x 1.25ms = 15ms.
-CONFIG_BT_PERIPHERAL_PREF_MAX_INT=12
-# Slave latency 0: do not skip connection events.
+# Preferred minimum connection interval: 24 x 1.25ms = 30ms
+CONFIG_BT_PERIPHERAL_PREF_MIN_INT=24
+# Preferred maximum connection interval: 48 x 1.25ms = 60ms
+CONFIG_BT_PERIPHERAL_PREF_MAX_INT=48
+# Slave latency 0: do not skip connection events
 CONFIG_BT_PERIPHERAL_PREF_LATENCY=0
 # Supervision timeout: 1000 x 10ms = 10s.
 CONFIG_BT_PERIPHERAL_PREF_TIMEOUT=1000
diff --git a/src/ble/ble_service.c b/src/ble/ble_service.c
index b5cec68..e6b54c9 100644
--- a/src/ble/ble_service.c
+++ b/src/ble/ble_service.c
@@ -661,7 +661,7 @@ static void le_param_updated(struct bt_conn *conn, uint16_t interval, uint16_t l
 {
     ARG_UNUSED(conn);
 
-    DBG_PRINTF("[BLE] Params: interval=%u(%u.%01ums) latency=%u timeout=%u(%ums)\r\n",
+    DBG_PRINTF("[BLE] Conn param updated: interval=%u(%u.%01ums) latency=%u timeout=%u(%ums)\r\n",
                interval,
                (interval * 125U) / 100U,
                ((interval * 125U) % 100U) / 10U,
diff --git a/src/ble/ble_service.h b/src/ble/ble_service.h
index 16ec9b4..168a199 100644
--- a/src/ble/ble_service.h
+++ b/src/ble/ble_service.h
@@ -14,8 +14,8 @@
 #define APP_ADV_INTERVAL            64      // 64 x 0.625ms = 40ms
 #define APP_ADV_DURATION            60000   // 60000 x 10ms = 600s (10 min)
 
-#define BLE_MIN_CONN_INTERVAL       12      // 15ms / 1.25ms = 12
-#define BLE_MAX_CONN_INTERVAL       24      // 24ms / 1.25ms = 24
+#define BLE_MIN_CONN_INTERVAL       24      // 30ms / 1.25ms = 24
+#define BLE_MAX_CONN_INTERVAL       48      // 60ms / 1.25ms = 48
 #define BLE_SLAVE_LATENCY           0
 #define BLE_CONN_SUP_TIMEOUT        1000    // 10000ms / 10ms = 1000
 
diff --git a/src/ble/ble_tx_power.c b/src/ble/ble_tx_power.c
index 09e9c3f..20229ff 100644
--- a/src/ble/ble_tx_power.c
+++ b/src/ble/ble_tx_power.c
@@ -18,9 +18,9 @@
 #define BLE_RSSI_STRESS_DBM            (-80)
 #define BLE_RSSI_STRESS_COUNT          3
 #define BLE_RSSI_MONITOR_INTERVAL_MS   2000
-#define BLE_TX_SLOW_MS                 50
-#define BLE_TX_CRITICAL_MS             100
-#define BLE_TX_STUCK_MS                200
+#define BLE_TX_SLOW_MS                 100
+#define BLE_TX_CRITICAL_MS             200
+#define BLE_TX_STUCK_MS                500
 #define BLE_TX_SLOW_COUNT              3
 #define BLE_TX_BUSY_STRESS_RETRY       4
 #define BLE_TX_RECOVER_HOLD_MS         10000
diff --git a/src/main.h b/src/main.h
index 0f50d2e..df4c81b 100644
--- a/src/main.h
+++ b/src/main.h
@@ -18,7 +18,7 @@
 #define HARDWARE_VERSION        "VB0HW0000"
 #define SERIAL_NUMBER           "VBT2608000Z"
 #define DEFAULT_PASSKEY         "123456"
-#define FIRMWARE_VERSION        "VBTFW0204"
+#define FIRMWARE_VERSION        "VBTFW0205"
 
 /*
 * Firmware Version History
@@ -28,6 +28,7 @@
  * 2026-08-05 | VBTFW0202  | 2.0.2+0       | Added production command(mpd?)
  * 2026-08-25 | VBTFW0203  | 2.0.3+0       | Fixed piezo power on/off timing, piezo sweep timing, and BLE settings
  * 2026-08-28 | VBTFW0204  | 2.0.4+0       | Align IMU direct read(mbb?) FSR with FIFO scale
+ * 2026-08-28 | VBTFW0205  | 2.0.5+0       | Fixed BLE connection interval(15~30ms -> 30~60ms) for battery life improvement
 */
 
 /*==============================================================================