Uboot不能下载程序到SDRAM中去运行

请帮忙看下:
我想用Uboot下载程序到SDRAM去,却发现不能下载,停在下载那里不动.信息如下:
#####    Boot for Nand Flash Main Menu  #####
[1] Download u-boot or STEPLDR.nb1 or other bootloader to Nand Flash
[2] Download Eboot to Nand Flash
[3] Download Linux Kernel to Nand Flash
[5] Download CRAMFS image to Nand Flash
[6] Download YAFFS image to Nand Flash
[7] Download Program (uCOS-II or TQ2440_Test) to SDRAM and Run it
[8] Boot the system
[9] Format the Nand Flash
[0] Set the boot parameters
[a] Download User Program (eg: uCOS-II or TQ2440_Test)
[b] Download LOGO Picture (.bin) to Nand  Flash
[l] Set LCD Parameters
[r] Reboot u-boot
[t] Test Linux Image (zImage)
[q] quit from menu
Enter your selection: 7
USB host is connected. Waiting a download.

Now, Downloading [ADDRESS:3000000h,TOTAL:457566]
RECEIVED FILE SIZE:       0
不管我怎么试,都是出现"RECEIVED FILE SIZE:       0"
无法下载程序到SDRAM中去,但选其它的下载,都能成功.我试了选取1和A两个下载都成功了,只有选7就不成功,请技术支持帮助解决.

很简单，在TQ2440使用手册的附录中有个设置DNW的章节，在哪里设置的是0x30000000，而你设置成了0x3000000，你少了一个0.

呵呵,版主不愧是版主,我今天下午下班回来调试才发现是这个原因,希望以后第一次使用DNW的朋友们都注意了,那个DNW默认的那个地址那里是0XC000000;只有7位,少了1位;我就是大意没去细看,只是将C改为3,结果当然不能从RAM里面读出程序运行了.教训深刻啊!