How can I get more space with H3C Magic NX30 Pro?

I install openwrt to H3C NX30 Pro but got 13.6MB to install software. How can I get more space with this router.

root@OpenWrt:~# cat /proc/mtd
dev:    size   erasesize  name
mtd0: 00100000 00020000 "BL2"
mtd1: 00080000 00020000 "u-boot-env"
mtd2: 00200000 00020000 "Factory"
mtd3: 00200000 00020000 "FIP"
mtd4: 04000000 00020000 "ubi"
mtd5: 00600000 00020000 "pdt_data"
mtd6: 00600000 00020000 "pdt_data_1"
mtd7: 00100000 00020000 "exp"
mtd8: 02580000 00020000 "plugin"

root@OpenWrt:~# ubinfo -a
UBI version:                    1
Count of UBI devices:           1
UBI control device major/minor: 10:256
Present UBI devices:            ubi0

ubi0
Volumes count:                           9
Logical eraseblock size:                 126976 bytes, 124.0 KiB
Total amount of logical eraseblocks:     512 (65011712 bytes, 62.0 MiB)
Amount of available logical eraseblocks: 0 (0 bytes)
Maximum count of volumes                 128
Count of bad physical eraseblocks:       0
Count of reserved physical eraseblocks:  20
Current maximum erase counter value:     5
Minimum input/output unit size:          2048 bytes
Character device major/minor:            250:0
Present volumes:                         0, 1, 2, 3, 4, 5, 6, 7, 8

Volume ID:   0 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        25 LEBs (3174400 bytes, 3.0 MiB)
State:       OK
Name:        kernel
Character device major/minor: 250:1
-----------------------------------
Volume ID:   1 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        87 LEBs (11046912 bytes, 10.5 MiB)
State:       OK
Name:        fit
Character device major/minor: 250:2
-----------------------------------
Volume ID:   2 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        25 LEBs (3174400 bytes, 3.0 MiB)
State:       OK
Name:        kernel2
Character device major/minor: 250:3
-----------------------------------
Volume ID:   3 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        141 LEBs (17903616 bytes, 17.0 MiB)
State:       OK
Name:        rootfs2
Character device major/minor: 250:4
-----------------------------------
Volume ID:   4 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        72 LEBs (9142272 bytes, 8.7 MiB)
State:       OK
Name:        recovery
Character device major/minor: 250:5
-----------------------------------
Volume ID:   5 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        5 LEBs (634880 bytes, 620.0 KiB)
State:       OK
Name:        u-boot-env
Character device major/minor: 250:6
-----------------------------------
Volume ID:   6 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        9 LEBs (1142784 bytes, 1.0 MiB)
State:       OK
Name:        ubootenv
Character device major/minor: 250:7
-----------------------------------
Volume ID:   7 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        9 LEBs (1142784 bytes, 1.0 MiB)
State:       OK
Name:        ubootenv2
Character device major/minor: 250:8
-----------------------------------
Volume ID:   8 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        113 LEBs (14348288 bytes, 13.6 MiB)
State:       OK
Name:        rootfs_data
Character device major/minor: 250:9

Create ubootmod for it, or extroot, if there's an USB port.