Cannot boot at Dargon Board

I am using Arrow Dargon Board and AD-96TOF1-EBZ to run the demo program (provide from the AD-96TOF1-EBZ ).

I can run the boot up to Linux OS with GUI and run demo program successful initially.

After I restart the dargon board (by the GUI - then click the rebot device), the Dargon board cannot boot to Linux OS with GUI. It shows the following two lines:

Debian GNU/Linux 9 linaro-alip tty1

linaro-alip login:

Since I don't have much knowladge about Linux. May I have some suggestion to run the demo program.

Or I need to reflash the SD image. If yes, may I have the original image on the SD card (come with AD-96TOF1-EBZ).