Leopard DM368开发板启动信息如下，并且网口的灯也不亮了：
我只是烧写了uImage、ramdisk，没有碰boot，怎么会出现下面的错误的
===============Message=============
DM36x initialization passed!
TI UBL Version: 1.50
Booting Catalog Boot Loader
BootMode = NAND
Starting NAND Copy...
No valid boot image found!
NAND Boot failed.
Aborting...
================Message===========
