[Yaffs] unusable yaffs partition

Hi all,
I am trying to add yaffs2 system partition in Android and flash it with
system.img file.
after defining mtd partitions I used flashed system.img into one of them
using
alternately nand write.yaffs and nand write. In both cases I have problems
after mounting system partition :

1- system partition is empty it only contains lost+found folder.
2- When I try to create a file in this partition It disappears as soon as I
reboot my card.


this is the contents of both /proc/yaffs and /proc/filesystems; I think
that they are both ok but I am not sure because I am a yaffs newbie.

============================================

/system # cat /proc/yaffs
YAFFS built:Oct 23 2013 11:54:54


Device 0 "system"
start_block........... 0
end_block............. 1439
total_bytes_per_chunk. 2048
use_nand_ecc.......... 0
no_tags_ecc........... 0
is_yaffs2............. 1
inband_tags........... 0
empty_lost_n_found.... 0
disable_lazy_load..... 0
refresh_period........ 500
n_caches.............. 10
n_reserved_blocks..... 5
always_check_erased... 0
data_bytes_per_chunk.. 2048
chunk_grp_bits........ 0
chunk_grp_size........ 1
n_erased_blocks....... 1406
blocks_in_checkpt..... 0

n_tnodes.............. 0
n_obj................. 4
n_free_chunks......... 89984

n_page_writes......... 0
n_page_reads.......... 0
n_erasures............ 0
n_gc_copies........... 0
all_gcs............... 0
passive_gc_count...... 0
oldest_dirty_gc_count. 0
n_gc_blocks........... 0
bg_gcs................ 0
n_retired_writes...... 0
n_retired_blocks...... 0
n_ecc_fixed........... 0
n_ecc_unfixed......... 0
n_tags_ecc_fixed...... 0
n_tags_ecc_unfixed.... 0
cache_hits............ 0
n_deleted_files....... 0
n_unlinked_files...... 0
refresh_count......... 1
n_bg_deletions........ 0


============================================

/system # cat /proc/filesystems
nodev   sysfs
nodev   rootfs
nodev   bdev
nodev   proc
nodev   tmpfs
nodev   devtmpfs
nodev   binfmt_misc
nodev   debugfs
nodev   sockfs
nodev   usbfs
nodev   pipefs
nodev   anon_inodefs
nodev   rpc_pipefs
nodev   devpts
        ext3
        ext2
        ext4
        cramfs
nodev   ramfs
        vfat
        msdos
        iso9660
nodev   nfs
nodev   nfs4
        yaffs
        yaffs2
nodev   mqueue
nodev   mtd_inodefs
nodev   oprofilefs
nodev   ubifs

============================================

Could you please help me solving this problem ?

Thanks,
Bill