在10.0 11.0的产品由于没有音量键 所以用音量键和电源键来选择recovery模式就无法实现了 所以当进入
recovery选择模式界面 就一直停在那里 根据需要 要修改成进入等待用户选择recovery模式时，直接
恢复出厂设置就好
先看recovery_main.cpp代码如下
路径:bootable\recovery\recovery_main.cpp
int main(int argc, char** argv) {
// We don't have logcat yet under recovery; so we'll print error on screen and log to stdout
// (which is redirected to recovery.log) as we used to do.
android::base::InitLogging(argv, &UiLogger);
// Take last pmsg contents and rewrite it to the current pmsg session