diff --git a/src/pages/device/composables/useDeviceStatus.js b/src/pages/device/composables/useDeviceStatus.js
index d7b8dd6..d99eefb 100644
--- a/src/pages/device/composables/useDeviceStatus.js
+++ b/src/pages/device/composables/useDeviceStatus.js
@@ -11,8 +11,10 @@ export function useDeviceStatus({
   user,
   device,
   deviceStatus,
+  deviceUsageDuration,
   online,
   updateDevice,
+  updateDeviceUsageDuration,
   clearDevice,
   unbindDialogVisible,
 }) {
@@ -41,14 +43,28 @@ export function useDeviceStatus({
   const batteryText = computed(() =>
     battery.value === null ? "暂无数据" : `${battery.value}%`
   );
+  const normalizeDuration = (value) => {
+    if (value == null || String(value).trim() === "") return null;
+    const seconds = Number(value);
+    return Number.isFinite(seconds) && seconds >= 0 ? seconds : null;
+  };
+
   const onlineDurationText = computed(() => {
-    const rawDuration = deviceStatus.value.onlineDuration;
-    if (rawDuration == null || String(rawDuration).trim() === "") return "--";
+    const currentDeviceId = String(device.value.deviceId || "");
+    const cachedDuration =
+      String(deviceUsageDuration.value.deviceId || "") === currentDeviceId
+        ? normalizeDuration(deviceUsageDuration.value.seconds)
+        : null;
+    const durations = [
+      normalizeDuration(deviceStatus.value.onlineDuration),
+      normalizeDuration(deviceDetails.value.onlineDuration),
+      cachedDuration,
+    ].filter((value) => value !== null);
 
-    const seconds = Number(rawDuration);
-    if (!Number.isFinite(seconds) || seconds < 0) return "--";
+    if (!durations.length) return "--";
+    const seconds = Math.max(...durations);
 
-    // WS 推送秒数，页面按完整分钟展示累计使用时间。
+    // 累计时长应单调递增，页面按完整分钟展示当前已知最大值。
     const totalMinutes = Math.floor(seconds / 60);
     const hours = Math.floor(totalMinutes / 60);
     const minutes = totalMinutes % 60;
@@ -109,6 +125,7 @@ export function useDeviceStatus({
           detail.qrCodeUrl ?? deviceDetails.value.qrCodeUrl ?? ""
         ).trim(),
       };
+      updateDeviceUsageDuration(detail.onlineDuration, deviceId);
     } catch (error) {
       // 实时刷新失败时保留当前页面数据，等待下次通知或页面重新显示。
       console.log("刷新设备详情失败", error);
@@ -158,6 +175,7 @@ export function useDeviceStatus({
             latestDevice.name ||
             "我的智能弓"
         );
+        updateDeviceUsageDuration(latestDevice.onlineDuration, latestDevice.deviceId);
         return;
       }
       clearDevice();
diff --git a/src/pages/device/my-device.vue b/src/pages/device/my-device.vue
index 596acd0..01ccfe9 100644
--- a/src/pages/device/my-device.vue
+++ b/src/pages/device/my-device.vue
@@ -22,8 +22,8 @@ import {
 import { useOtaUpdate } from "@/composables/useOtaUpdate";
 
 const store = useStore();
-const { updateDevice, clearDevice } = store;
-const { user, device, deviceStatus, online } = storeToRefs(store);
+const { updateDevice, updateDeviceUsageDuration, clearDevice } = store;
+const { user, device, deviceStatus, deviceUsageDuration, online } = storeToRefs(store);
 const DEVICE_NAME_MAX_LENGTH = 10;
 
 const formatBindingDate = (value) => {
@@ -97,8 +97,10 @@ const {
   user,
   device,
   deviceStatus,
+  deviceUsageDuration,
   online,
   updateDevice,
+  updateDeviceUsageDuration,
   clearDevice,
   unbindDialogVisible,
 });
@@ -112,6 +114,28 @@ const bindingDateText = computed(() =>
   formatBindingDate(deviceDetails.value.bindTime)
 );
 
+// 固件版本统一以大写 V 开头，避免接口返回格式不一致影响弹窗展示。
+const formatFirmwareVersion = (value) => {
+  const version = String(value ?? "").trim();
+  if (!version) return "";
+  return /^v/i.test(version) ? `V${version.slice(1)}` : `V${version}`;
+};
+
+const firmwareConfirmContent = computed(() => {
+  const currentVersion = formatFirmwareVersion(deviceStatus.value.version);
+  const latestVersion = formatFirmwareVersion(
+    pendingOtaInfo.value?.versionNumber
+  );
+
+  if (currentVersion && latestVersion) {
+    return `当前固件版本为 ${currentVersion}，发现新固件版本 ${latestVersion}，是否立即更新固件？`;
+  }
+  if (latestVersion) {
+    return `发现新固件版本 ${latestVersion}，是否立即更新固件？`;
+  }
+  return "发现新固件版本，是否立即更新固件？";
+});
+
 const deviceIdText = computed(() =>
   showDeviceId.value && device.value.deviceName
     ? device.value.deviceName
@@ -519,7 +543,7 @@ onShow(async () => {
           class="device-bow"
           :class="{ 'device-bow--online': isDeviceOnline }"
           :src="isDeviceOnline
-            ? 'https://static.shelingxingqiu.com/shootmini/static/home-device/device-bow--online.png'
+            ? 'https://static.shelingxingqiu.com/shootmini/static/home-device/device-bow.png'
             : 'https://static.shelingxingqiu.com/shootmini/static/home-device/device-bow.png'"
           :mode="isDeviceOnline ? 'aspectFit' : 'widthFix'"
         />
@@ -697,9 +721,9 @@ onShow(async () => {
     <ModalDialog
       :show="firmwareConfirmVisible"
       title="固件更新"
-      content="是否现在进行固件更新？"
-      cancelText="取消"
-      confirmText="确定"
+      :content="firmwareConfirmContent"
+      cancelText="暂不更新"
+      confirmText="立即更新"
       :onCancel="closeFirmwareConfirm"
       :onConfirm="confirmFirmwareUpdate"
     ></ModalDialog>
@@ -975,7 +999,7 @@ onShow(async () => {
 
 .device-bow {
   position: absolute;
-  top: 0;
+  top: -2rpx;
   left: 50%;
   z-index: 4;
   width: 562rpx;
diff --git a/src/static/home-device/device-bow.png b/src/static/home-device/device-bow.png
index c5b5db3..d94ea85 100644
Binary files a/src/static/home-device/device-bow.png and b/src/static/home-device/device-bow.png differ
diff --git a/src/store.js b/src/store.js
index d75639a..3774d66 100644
--- a/src/store.js
+++ b/src/store.js
@@ -27,6 +27,11 @@ const getDefaultDeviceStatus = () => ({
   receivedAt: 0,
 });
 
+const getDefaultDeviceUsageDuration = () => ({
+  deviceId: "",
+  seconds: null,
+});
+
 const getDefaultGame = () => ({
   roomID: "",
   inBattle: false,
@@ -114,6 +119,8 @@ export default defineStore("store", {
     deviceBattery: null,
     // WebSocket 实时推送的设备状态，不参与持久化。
     deviceStatus: getDefaultDeviceStatus(),
+    // 按设备记录本次运行期间已知的最大累计使用时长，离线时保持数值不回退。
+    deviceUsageDuration: getDefaultDeviceUsageDuration(),
     game: {
       roomID: "",
       inBattle: false,
@@ -183,6 +190,27 @@ export default defineStore("store", {
       this.deviceStatus = nextStatus;
       this.online = online;
       this.deviceBattery = online ? nextStatus.battery : null;
+      this.updateDeviceUsageDuration(nextStatus.onlineDuration);
+    },
+    updateDeviceUsageDuration(value, deviceId = this.device.deviceId) {
+      if (value === null || value === undefined || String(value).trim() === "") return;
+
+      const seconds = Number(value);
+      const normalizedDeviceId = String(deviceId || "");
+      if (!normalizedDeviceId || !Number.isFinite(seconds) || seconds < 0) return;
+
+      const cachedDeviceId = String(this.deviceUsageDuration.deviceId || "");
+      const cachedSeconds = Number(this.deviceUsageDuration.seconds);
+      this.deviceUsageDuration = {
+        deviceId: normalizedDeviceId,
+        seconds:
+          cachedDeviceId === normalizedDeviceId && Number.isFinite(cachedSeconds)
+            ? Math.max(cachedSeconds, seconds)
+            : seconds,
+      };
+    },
+    clearDeviceUsageDuration() {
+      this.deviceUsageDuration = getDefaultDeviceUsageDuration();
     },
     setDeviceOnline(online) {
       const nextOnline = online === true;
@@ -210,6 +238,7 @@ export default defineStore("store", {
     updateDevice(deviceId, deviceName) {
       if (String(this.device.deviceId || "") !== String(deviceId || "")) {
         this.clearDeviceStatus();
+        this.clearDeviceUsageDuration();
       }
       this.device.deviceId = deviceId;
       this.device.deviceName = deviceName;
@@ -217,6 +246,7 @@ export default defineStore("store", {
     clearDevice() {
       this.device = getDefaultDevice();
       this.clearDeviceStatus();
+      this.clearDeviceUsageDuration();
     },
     async updateConfig(config) {
       this.config = config;
@@ -267,6 +297,7 @@ export default defineStore("store", {
         online: false,
         deviceBattery: null,
         deviceStatus: getDefaultDeviceStatus(),
+        deviceUsageDuration: getDefaultDeviceUsageDuration(),
         game: getDefaultGame(),
         dailyCount: getDefaultDailyCount(),
         deviceChargingDialogVisible: false,