[U-Boot] RAMdisk with uboot on s3c2440

[Gigin Jose]

Hi , 
I am working on S3C2440. I need to load the initrd with the uboot. The base address for my RAM is 0x30000000. As per the documentations, the kernel is loaded to 0x30008000 and the initrd is loaded to 0x30800000. On the NAND flash, zImage is loaded at address 0x200000. I loaded the ramdisk to 0x140000 using the following commands: 
"tftp 30000000 initramfs.uboot""nand erase 140000 4b5e1""nand write.jffs2 0x30000000 0x140000 4b5e1"

 I am using 64 MB nand. 4b5e1 is the size of ramdisk in hexa. 
After loading on the nand flash, I copied the ramdisk to 0x30800000 ("cp.b 140000 30800000 4b5e1") and checked the image with iminfo 30800000 command on the uboot. I get an error "Bad Magic Number". why is it so ? Once I download the the initramfs.uboot to 0x30000000 using tftp and check the image using iminfo, I get the following message. 
## Checking Image at 30000000 ...
   Image Name:   
   Created:      2011-01-04  14:24:02 UTC
   Image Type:   ARM Linux RAMDisk Image (gzip compressed)
   Data Size:    308641 Bytes = 301.4 kB
   Load Address: 30800000
   Entry Point:  00000000
   Verifying Checksum ... OK . 
Why am I not able to burn the ramdisk image to NAND flash.? Is there anything wrong with NAND flash address or with the copy command ? 
thanks & regardsGIGIN