Quoted from following article which is important:
Please read both as they cover in detail the process of creating a root file system and getting in on a flash device. Using the /dev/mtd* devices isn't recommended. The root file system should be created with the mkfs.jffs2 utility and put on the flash with nandwrite.
https://linuxlink.timesys.com/forum/1746
nandwrite的用法详细见:
http://blog.youkuaiyun.com/yinkaizhong/archive/2008/12/25/3604794.aspx