重新烧写uboot和uImage

首先具备文件，tftp，uImage_hi3559av100_multi-core，rootfs_hi3559av100_2k_24bit.yaffs2，uImagewenjian

启动uboot时按回车进入烧写模式
查看环境变量printenv
设置自己的电脑ip，setenv serverip 用于tftp使用
设置设备ip，setenv ipaddr
mw.b 0x44000000 0xff 0x900000 //
tftp 0x44000000 uImage_hi3559av100_multi-core //需要写入文件的名称
nand erase 0x100000 0x900000 //擦除0x100000开始的9兆空间
nand write 0x44000000 0x100000 0x900000 //从0x44000000位置偏移0x100000开始写文件，占用空间为9兆

mw.b 0x44000000 0xff 0x1000000 //
tftp 0x44000000 rootfs_hi3559av100_2k_24bit.yaffs2 //同上
nand erase 0xa00000 0x1000000 //同上
nand write.yaffs 0x44000000 0xa00000 $(filesize) //同上，filesize大小为printenv环境变量显示的filesize

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mw.b 0x42000000 0xff 0x900000
tftp 0x42000000 uImage_hi3559av100_multi-core
nand erase 0x100000 0x900000
nand write 0x42000000 0x100000 0x900000

mw.b 0x42000000 0xff 0x1000000
tftp 0x42000000 rootfs_hi3559av100_2k_24bit.yaffs2
nand erase 0xa00000 0x2000000
nand write.yaffs 0x42000000 0xa00000 $(filesize)