boot param for exmple

bootargs=mem=320M quiet root=/dev/ram rw rootfstype=ext2 mtdparts=hinand:1M(boot),1M(env),4M(kernel),15M(rootfs),99M(data),4M(system),4M(logo) libata.force=noncq
bootcmd=nand read 0x82000000 0x200000 0x400000; nand read 0x82400000 0x600000 0xF00000; bootm 0x82000000 0x82400000
bootdelay=1
baudrate=115200
ipaddr=192.168.0.188
serverip=192.168.0.125
netmask=255.255.255.0
bootfile="uImage"
1=mw.b 0x82000000 0xFF 0x80000;if tftp 0x82000000 hi3531_uboot.bin;then nand erase 0 0x80000;nand write 0x82000000 0 0x80000;fi
2=mw.b 0x82000000 0xFF 0x400000;if tftp 0x82000000 hi3531_kernel.bin;then nand erase 0x200000 0x400000;nand write 0x82000000 0x200000 0x400000;fi
3=mw.b 0x82000000 0xFF 0xF00000;if tftp 0x82000000 hi3531_rootfs.ext2;then nand erase 0x600000 0xF00000;nand write 0x82000000 0x600000 0xF00000;fi
4=mw.b 0x82000000 0xFF 0x6300000
5=if tftp 0x82000000 hi3531_data.jffs2;then nand erase 0x1500000 0x6300000;nand write.jffs2 0x82000000 0x1500000 0x6300000;fi
logo=mw.b 0x82000000 0xFF 0x400000;if tftp 0x82000000 samsung_logo.bin;then nand erase 0x7C00000 0x400000;nand write 0x82000000 0x7C00000 0x400000;fi
6=run 1 2 3 4 5 logo
7=run 6;reset
del_env=nand erase 0x100000 0x80000
del_sys=nand erase 0x7800000 0x400000
stdin=serial
stdout=serial
stderr=serial
verify=n
ver=U-Boot 2010.06-svn1258 (Feb 27 2013 - 18:07:10)
ntsc=1
board_ID=0x801b
ethaddr=00:09:18:03:75:FF
jpeg_addr=0x92280000
fileaddr=92280000
vobuf=0xD3000000
jpeg_size=0x80000
filesize=80000

Environment size: 1469/262140 bytes

其中bootcmd=nand read 0x82000000 0x200000 0x400000; nand read 0x82400000 0x600000 0xF00000; bootm 0x82000000 0x82400000  

nand read 0x82000000 0x200000 0x400000 表示从nand flash 地址0x200000 读4M 为kernel image 到内存地址0x82000000 上; bootm 为从0x82000000 启动到内存地址0x82400000