问题描述：
测试环境：1 插入SD卡；2 已经开启数据流量或是连接可用的WIFI网络
测试步骤：进入OTA升级客户端（第三方）1-进入OTA客户端选择在线升级；2 升级过程中使用数据线连接手机到PC端，并打开USB存储设备
测试结果：在线升级下载界面出现"下载失败"讯息
首先，OTA升级客户端下载的更新包存储机制是内置存储优先原则；系统主存储机制为SD卡优先原则，那么基于以上两个原则现在对问题进行分析，读者可以参考下面关键log：
第一部分：下载过程中，打开USB存储设备
第一步：确定复现时间点的log标志信息
02-09 15:39:08.333: E/HwOUC(4739): [main-1]report download failure! stauts is 492(hwouc/FirmwareAndAppReceiver.java:87)
上面log信息可以看到当前下载更新失败，status is 492则表示文件存储异常
第二步：排查打开USB存储设备时，存储设备挂载的log
02-09 15:39:01.284: V/ActivityManager(683): Broadcast: Intent { act=android.intent.action.MEDIA_EJECT dat=file:///storage/sdcard0 flg=0x10 (has extras) } ordered=false userid=-1 callerApp=ProcessRecord{42bd4580 683:system/1000}//将卸载SD卡，但SD卡上部分内容尚未处于打开状态02-09 15:39:01.301: V/ActivityManager(683): Broadcast: Intent { act=android.intent.action.MEDIA_EJECT dat=file:///storage/sdcard1 flg=0x10 (has extras) } ordered=false userid=-1 callerApp=ProcessRecord{42bd4580 683:system/1000}//将卸载SD卡，但SD卡上部分内容尚未处于打开状态
02-09 15:39:09.005: V/ActivityManager(683): Broadcast: Intent { act=android.intent.action.MEDIA_SCANNER_STARTED dat=file:///storage/sdcard1 flg=0x10 } ordered=false userid=0 callerApp=ProcessRecord{431144a8 1546:android.process.media/u0a5}////MediaScanner开始扫描内部存储
02-09 15:39:09.351: V/ActivityManager(683): Broadcast: Intent { act=android.intent.action.MEDIA_SCANNER_FINISHED dat=file:///storage/sdcard1 flg=0x10 } ordered=false userid=0 callerApp=ProcessRecord{431144a8 1546:android.process.media/u0a5}//扫描结束
02-09 15:39:15.456: D/ActivityThread(7090): BDC-Calling onReceive: intent=Intent { act=android.intent.action.MEDIA_SHARED dat=file:///storage/sdcard1 flg=0x10 cmp=com.mediatek.mtklogger/.framework.LogReceiver (has extras) }, ordered=true, receiver=com.mediatek.mtklogger.framework.LogReceiver@42870ee0//进入USB连接模式，SD卡被卸载，终端将无法访问SD卡
第三步：那么考虑到前面提到的两种机制，在参考第二步所提供的log，此时我们对存储路径的相关log进行分析如下：
02-09 15:38:57.510: I/StorageManagerEx(1546): getInternalStoragePath from Property path=/storage/sdcard1
02-09 15:38:57.510: D/StorageManagerEx(1546): getInternalStoragePath path=/storage/sdcard1
........
02-09 15:39:01.365: I/StorageManagerEx(7090): getInternalStoragePath from Property path=/storage/sdcard1
02-09 15:39:01.365: D/StorageManagerEx(7090): getInternalStoragePath path=/storage/sdcard1
02-09 15:39:09.535: I/StorageManagerEx(7090): getInternalStoragePath from Property path=/storage/sdcard0
02-09 15:39:09.536: D/StorageManagerEx(7090): getInternalStoragePath path=/storage/sdcard0
........
02-09 15:39:26.452: I/StorageManagerEx(1546): getInternalStoragePath from Property path=/storage/sdcard0
02-09 15:39:26.464: D/StorageManagerEx(1546): getInternalStoragePath path=/storage/sdcard0
从上面log我们可以看到，在打开USB存储设备之前，主存储为SDCard，SDCard路径为/storage/sdcard0；而内部存储为/storage/sdcard1；在打开USB存储设备之后，主存储为内部存储，内部内存储的路径为/storage/sdcard0。
第二部分：连接打开USB存储设备重新下载，下载过程中关闭USB存储设备的分析
第一步：确定复现时间点的log标志信息如下：
02-09 15:40:21.419: E/HwOUC(4739): [main-1]report download failure! stauts is 492(hwouc/FirmwareAndAppReceiver.java:87)
上面log信息可以看到当前下载更新失败，status is 492则表示文件存储异常
第二步：排查打开USB存储设备时，存储设备挂载的log
02-09 15:40:11.630: V/ActivityManager(683): Broadcast: Intent { act=android.intent.action.MEDIA_UNSHARED dat=file:///storage/sdcard1 flg=0x10 (has extras) } ordered=false userid=-1 callerApp=ProcessRecord{42bd4580 683:system/1000}//退出USB存储模式
02-09 15:40:11.631: V/ActivityManager(683): Broadcast: Intent { act=android.intent.action.MEDIA_EJECT dat=file:///storage/sdcard0 flg=0x10 (has extras) } ordered=false userid=-1 callerApp=ProcessRecord{42bd4580 683:system/1000}//
02-09 15:40:11.637: V/ActivityManager(683): Broadcast: Intent { act=android.intent.action.MEDIA_UNMOUNTED dat=file:///storage/sdcard1 flg=0x10 (has extras) } ordered=false userid=-1 callerApp=ProcessRecord{42bd4580 683:system/1000}//SD卡被卸载，但并未移除SD卡
02-09 15:40:11.637: V/MediaProvider(1546): unmountReceiver: intent=Intent { act=android.intent.action.MEDIA_EJECT dat=file:///storage/sdcard0 flg=0x10 (has extras) }//将卸载SD卡，但SD卡上部分内容尚未处于打开状态
02-09 15:40:16.174: V/ActivityManager(683): Broadcast: Intent { act=android.intent.action.MEDIA_CHECKING dat=file:///storage/sdcard0 flg=0x10 (has extras) } ordered=false userid=-1 callerApp=ProcessRecord{42bd4580 683:system/1000}//正在检测SD卡
02-09 15:40:17.412: V/ActivityManager(683): Broadcast: Intent { act=android.intent.action.MEDIA_MOUNTED dat=file:///storage/sdcard0 flg=0x10 (has extras) } ordered=false userid=-1 callerApp=ProcessRecord{42bd4580 683:system/1000}//SD卡已挂载
02-09 15:40:17.656: V/MediaProvider(1546): unmountReceiver: intent=Intent { act=android.intent.action.MEDIA_MOUNTED dat=file:///storage/sdcard0 flg=0x10 (has extras) }//SD卡已挂载
02-09 15:40:18.621: V/ActivityManager(683): Broadcast: Intent { act=android.intent.action.MEDIA_SCANNER_STARTED dat=file:///storage/sdcard0 flg=0x10 } ordered=false userid=0 callerApp=ProcessRecord{431144a8 1546:android.process.media/u0a5}//SD卡挂载后MediaScanner开始进行扫描
02-09 15:40:28.474: V/ActivityManager(683): Broadcast: Intent { act=android.intent.action.MEDIA_SCANNER_FINISHED dat=file:///storage/sdcard0 flg=0x10 } ordered=false userid=0 callerApp=ProcessRecord{431144a8 1546:android.process.media/u0a5}//扫描结束
第三步：那么考虑到前面提到的两种机制，在参考第二步所提供的log，此时我们对存储路径的相关log进行分析如下：
02-09 15:40:09.631: I/StorageManagerEx(7090): getInternalStoragePath from Property path=/storage/sdcard0
02-09 15:40:09.631: D/StorageManagerEx(7090): getInternalStoragePath path=/storage/sdcard0
........
02-09 15:40:11.669: I/StorageManagerEx(7090): getInternalStoragePath from Property path=/storage/sdcard0
02-09 15:40:11.669: D/StorageManagerEx(7090): getInternalStoragePath path=/storage/sdcard0
02-09 15:40:15.616: I/StorageManagerEx(7090): getInternalStoragePath from Property path=/storage/sdcard1
02-09 15:40:15.616: D/StorageManagerEx(7090): getInternalStoragePath path=/storage/sdcard1
........
02-09 15:40:16.043: I/StorageManagerEx(7090): getInternalStoragePath from Property path=/storage/sdcard1
02-09 15:40:16.043: D/StorageManagerEx(7090): getInternalStoragePath path=/storage/sdcard1
从上面log我们可以看到，在关闭USB存储设备之前，主存储为内部存储，而内部存储为/storage/sdcard0；在关闭USB存储设备之后，主存储为SD卡，内部内存储的路径为/storage/sdcard1。
因此，总的来说当前问题是由于打开USB存储导致内部存储路径发生变化导致。