[Yaffs] The mounted yaffs2 file system just has a lost+found…

Please forgive me if this is not the place to ask such kind of questions.

I checkout the latest yaffs2 code and patched to kernel. The kernel options are:

<*> YAFFS2 file system support
-*-   512 byte / page devices
[ ]     Use older-style on-NAND data format with pageStatus byte
[ ]       Lets Yaffs do its own ECC
-*-   2048 byte (or larger) / page devices
[*]     Autoselect yaffs2 format
[ ]     Disable lazy loading
[ ]   Turn off wide tnodes
[ ]   Force chunk erase check
[*]   Cache short names in RAM

I created a yaffs2 file system with mkyaffs2image, and then I "burned" the image to flash:
flash_eraseall /dev/mtd2
nandwrite -a -o /dev/mtd2 ./rootfs.yaffs2

After successfully (?) mounting the root fs I found there is nothing except a empty lost+found directory.
kernel version: 2.6.24.
Flash type: (Sumsung K9F4G08U0A)

I appreciate your help.