wrt22
ubinfo -a
UBI version:                    1
Count of UBI devices:           1
UBI control device major/minor: 10:62
Present UBI devices:            ubi0

ubi0
Volumes count:                           3
Logical eraseblock size:                 126976 bytes, 124.0 KiB
Total amount of logical eraseblocks:     415 (52695040 bytes, 50.2 MiB)
Amount of available logical eraseblocks: 0 (0 bytes)
Maximum count of volumes                 128
Count of bad physical eraseblocks:       1
Count of reserved physical eraseblocks:  19
Current maximum erase counter value:     2
Minimum input/output unit size:          2048 bytes
Character device major/minor:            245:0
Present volumes:                         0, 1, 2

Volume ID:   0 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        38 LEBs (4825088 bytes, 4.6 MiB)
State:       OK
Name:        kernel
Character device major/minor: 245:1
-----------------------------------
Volume ID:   1 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        90 LEBs (11427840 bytes, 10.8 MiB)
State:       OK
Name:        rootfs
Character device major/minor: 245:2
-----------------------------------
Volume ID:   2 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        264 LEBs (33521664 bytes, 31.9 MiB)
State:       OK
Name:        rootfs_data


wrt23

ubinfo -a
UBI version:                    1
Count of UBI devices:           1
UBI control device major/minor: 10:126
Present UBI devices:            ubi0

ubi0
Volumes count:                           4
Logical eraseblock size:                 126976 bytes, 124.0 KiB
Total amount of logical eraseblocks:     415 (52695040 bytes, 50.2 MiB)
Amount of available logical eraseblocks: 0 (0 bytes)
Maximum count of volumes                 128
Count of bad physical eraseblocks:       1
Count of reserved physical eraseblocks:  19
Current maximum erase counter value:     3
Minimum input/output unit size:          2048 bytes
Character device major/minor:            245:0
Present volumes:                         0, 1, 2, 3

Volume ID:   0 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        38 LEBs (4825088 bytes, 4.6 MiB)
State:       OK
Name:        kernel
Character device major/minor: 245:1
-----------------------------------
Volume ID:   1 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        172 LEBs (21839872 bytes, 20.8 MiB)
State:       OK
Name:        ubi_rootfs
Character device major/minor: 245:2
-----------------------------------
Volume ID:   2 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        90 LEBs (11427840 bytes, 10.8 MiB)
State:       OK
Name:        rootfs
Character device major/minor: 245:3
-----------------------------------
Volume ID:   3 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        92 LEBs (11681792 bytes, 11.1 MiB)
State:       OK
Name:        rootfs_data
Character device major/minor: 245:4