cc2541 OAD 失败

SimpleBLEPeripheral工程，编译出来的OAD_ImgA及OAD_ImgB，按照OAD升级文档操作，使用TI BLE Multitool升级OAD_ImgB，进度条显示100%，却弹框显示如下信息，非必现，也有可能提示升级正常。

“FW Upgrade Failed

Device did not disconnect after programming as it should.  Firmware upgrade failed, you should check battery and settings.”

请教大神是否遇到过同样问题，这种情况升级是确实失败了，还是APP的显示问题？

PS：测试手机是Iphone 5s ，系统是IOS7.1.2， TI BLE Multitool是APP store最新版本。