请问bootcmd在u-boot里面是如何设置的？

SMDK2410 # set bootcmd nand read 30000000 kernel ;bootm 30000000
## Booting kernel from Legacy Image at 30000000 ...
   Image Name:   Linux-3.4.2
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    2063168 Bytes = 2 MiB
   Load Address: 30008000
   Entry Point:  30008000
   Verifying Checksum ... Bad Data CRC
ERROR: can't get kernel image!
为什么我每次设置BOOTCMD总是错误，请问下bootcmd 在u-boot里面是如何设置的？