Raspberrypi Boot from USB drive

Name	Version
HW	Raspberrypi 3B v1.2
OS	20180627

---

1. 启动树莓派

2. 开启USB启动模式：

# echo program_usb_boot_mode=1 | sudo tee -a /boot/config.txt

3. 重启树莓派，并检查设置

# vcgencmd otp_dump | grep 17:

输出应该为:

17:3020000a

4. 烧写系统到USB Drive

5. 拔掉存储卡，插入USB Drive，启动树莓派