[U-Boot] How to read and write a normal file from and to the yaffs2 in u-boot-2009.03 ?

Hello all:

I have a DaVinci DM6446 EVM board with 32MB K9F5608R0D(NAND Flash). The latest u-boot-2009.03 with yaffs2 compiled in can run on this board from Nand Flash. when running the command "ywr",the U-Boot dumps some error as such:

U-Boot > ywr /test.txt 0 5 Writing value (0) 5 times to /test.txt... yaffs tragedy: no more eraased blocks Error opening file: -1 done"

How to use the yaffs2 in u-boot-2009.03 ? Somebody can help me?

Thanks very much!

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