thanks i have upgraded version to b256 version .
now i can able to do use
sd card as bootable
root@Omega-BEA9:~# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/root                 7.8M      7.8M         0 100% /rom
tmpfs                    60.9M     96.0K     60.8M   0% /tmp
/dev/mmcblk0p1           14.5G     40.3M     13.7G   0% /overlay
overlayfs:/overlay       14.5G     40.3M     13.7G   0% /
tmpfs                   512.0K         0    512.0K   0% /dev
/dev/mmcblk0p1           14.5G     40.3M     13.7G   0% /mnt/mmcblk0p1
/dev/mtdblock6           22.1M    708.0K     21.4M   3% /mnt/mtdblock6
/dev/mtdblock7          512.0K    196.0K    316.0K  38% /mnt/mtdblock7