1. Using AndroidToool.

Download AndroidTool_v2.65.rar and DriverAssitant_v4.5.rar

https://github.com/ADVANTECH-Rockchip/rk3399_tools/tree/android_7.1.2_ks

Step1 Connect with the OTG port and PC.

Step2 Double click DriverInstall.

Step3 Enter into MASKROM mode .

There are two ways to enter MASKROM .

1. Hardware way to enter MASKROM

TBD

2. Software way to enter MASKROM

When the device boot up to android, you can use ADB or Debug console, send command "reboot loader" .

Or Press "ctrl + c" key when booting into uboot, until get the following information on debug console : 

Hit any key to stop autoboot: 0
rkboot # <INTERRUPT>
rkboot # loader

So the way need the device could boot up to android OS.

Click "Advantech Function" , then "Enter MASHROM" button to enter MASHROM mode .

Step4 Select the image path.

Step5 Finish the update