mtdinfo -a
ubiattach /dev/ubi_ctrl -m 4
mkfs.ubifs -m 2048  /dev/ubi0
ubimkvol /dev/ubi0 -N rootfs -t dynamic -m
mkfs.ubifs /dev/ubi0_0
mkdir /target
mount -t ubifs ubi0:rootfs /target
cp -a /bin /dev /etc /home /lib /media /mnt /opt /root /sbin /usr /var /target/ 
mkdir /target/sys
mkdir /target/proc
mkdir /target/tmp

df -h
rootfs                1.3G  147M  1.1G  12% /
ubi0:rootfs           227M   64M  164M  28% /target

umount /target
reboot

# uboot kernelcmdline
# setenv bootargs console=ttyO2,115200n8 ubi.mtd=4 root=ubi0:rootfs rootfstype=ubifs