OK6818-C 之前不小心用OTG模式烧写错了Android镜像。换了确定好的Linux镜像，在Ubuntu 14 下制好卡，复制好文件，拨好开关，串口输出信息如下
- scratch is broken, clear
- watchdog timer start
- working to aarch32
- waiting for pll change..
- --------------------------------------------------------------------------------
- Second Boot by Nexell Co. : Ver0.3.6 - Built on Jun 28 2019 18:53:19
- --------------------------------------------------------------------------------
- DDR3 POR Init Start 0
- DDR3 Init Done!
- CCI Init!
- Wakeup CPU Wakeup Sub CPU 1234567
- CPU Wakeup done! WFI is expected.
- CPU0 is Master!
- Loading from sdmmc...
- Image Loading Done!
- Launch to 0x40100000
不论SD卡烧写什么镜像，串口输出都是这样子。
