[U-Boot] "nand write.yaffs" is not working as expected

[Peter Pan]

I'm recently using YAFFS2 rootfs on our NAND flash. What I'm
experiencing is that
the u-boot console "nand write.yaffs" is not working.
With this image file, I can successfully write it to nand flash if I
boot into Linux. In
Linux console, I run "nandwrite -a -o /dev/mtd4 yaffs2.img". And then,
I can mount
the partition and see what's in it.

In u-boot, with the same yaffs2 image, I'm using "nand write.yaffs ${loadaddr}
${nandrootoffset} ${filesize}", and then I boot into Linux. I can only
see a "lost+found"
directory on that partition, nothing else.

Anyone ever met the same problem with this "nand write.yaffs" command? I'm
wondering maybe I did something wrong?