Error using ubiattach

I have a small 'ARMv7 Processor rev 2 (v7l)' powered box running Ubuntu 10.04 LTS with kernel 2.6.37 The environment is a squashfs rootfs with a small RW config area:

# dfFilesystem       1K-blocks      Used Available Use% Mounted on/dev/mtdblock11     246664    246664         0 100% /ubi1_0                6648       100      6548   2% /.profile

The box boots and operates without problems, however I am trying to access some of the /dev/mtd devices but receive errors when trying to attach:

# /usr/sbin/ubiattach /dev/ubi_ctrl -m 3ubiattach: error!: cannot attach mtd3           error 22 (Invalid argument)[2335587.812500] UBI: attaching mtd3 to ubi2[2335587.812500] UBI: physical eraseblock size:   131072 bytes (128 KiB)[2335587.812500] UBI: logical eraseblock size:    129024 bytes[2335587.812500] UBI: smallest flash I/O unit:    2048[2335587.812500] UBI: sub-page size:              512[2335587.812500] UBI: VID header offset:          512 (aligned 512)[2335587.812500] UBI: data offset:                2048[2335587.820312] UBI: max. sequence number:       0[2335587.820312] UBI error: ubi_read_volume_table: the layout volume was not found

Some devices I can access, but most I cannot. Example: /dev/mtd10 I can attach to but not /dev/mtd5

# /usr/sbin/mtdinfo /dev/mtd10 -umtd10Name:                           backupType:                           nandEraseblock size:                131072 bytes, 128.0 KiBAmount of eraseblocks:          320 (41943040 bytes, 40.0 MiB)Minimum input/output unit size: 2048 bytesSub-page size:                  512 bytesOOB size:                       64 bytesCharacter device major/minor:   90:20Bad blocks are allowed:         trueDevice is writable:             trueDefault UBI VID header offset:  512Default UBI data offset:        2048Default UBI LEB size:           129024 bytes, 126.0 KiBMaximum UBI volumes count:      128# /usr/sbin/mtdinfo /dev/mtd5 -umtd5Name:                           initrdType:                           nandEraseblock size:                131072 bytes, 128.0 KiBAmount of eraseblocks:          96 (12582912 bytes, 12.0 MiB)Minimum input/output unit size: 2048 bytesSub-page size:                  512 bytesOOB size:                       64 bytesCharacter device major/minor:   90:10Bad blocks are allowed:         trueDevice is writable:             trueDefault UBI VID header offset:  512Default UBI data offset:        2048Default UBI LEB size:           129024 bytes, 126.0 KiBMaximum UBI volumes count:      128

Added /proc/mtd output:

# cat /proc/mtd dev:    size   erasesize  namemtd0: 00080000 00020000 "mlo"mtd1: 00100000 00020000 "uboot-1"mtd2: 00100000 00020000 "uboot-2"mtd3: 00200000 00020000 "u-boot-env"mtd4: 00c00000 00020000 "kernel"mtd5: 00c00000 00020000 "initrd"mtd6: 00a00000 00020000 "miniinitrd"mtd7: 01400000 00020000 "atb-1"mtd8: 01400000 00020000 "atb-2"mtd9: 00a00000 00020000 "profile"mtd10: 02800000 00020000 "backup"mtd11: 17f80000 00020000 "root-fs"

Installed utilities are version 1.4.5

So, I'm looking for the answer to: why can't I attach?

I later was able to get the initrd partition from /dev/mtdblock5 with dd:

initrd.dd: u-boot legacy uImage, ATB:b35e7, Linux/ARM, RAMDisk Image (gzip), 3204472 bytes, Fri Nov 16 04:33:52 2012, Load Address: 0x00000000, Entry Point: 0x00000000, Header CRC: 0x19467C60, Data CRC: 0x04C77189

But have not been able to extract its contents:

$ gunzip -l - < initrd.ddgzip: stdin: not in gzip format