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UBI usage in U-Boot
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UBI support in U-Boot is broken down into five separate commands.
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The first is the ubi command, which has six subcommands:
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=> help ubi
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ubi - ubi commands
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Usage:
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ubi part [part] [offset]
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- Show or set current partition (with optional VID header offset)
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ubi info [l[ayout]] - Display volume and ubi layout information
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ubi create[vol] volume [size] [type] - create volume name with size
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ubi write[vol] address volume size - Write volume from address with size
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ubi write.part address volume size [fullsize]
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- Write part of a volume from address
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ubi read[vol] address volume [size] - Read volume to address with size
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ubi remove[vol] volume - Remove volume
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[Legends]
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volume: character name
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size: specified in bytes
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type: s[tatic] or d[ynamic] (default=dynamic)
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The first command that is needed to be issues is "ubi part" to connect
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one mtd partition to the UBI subsystem. This command will either create
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a new UBI device on the requested MTD partition. Or it will attach a
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previously created UBI device. The other UBI commands will only work
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when such a UBI device is attached (via "ubi part"). Here an example:
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=> mtdparts
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device nor0 <1fc000000.nor_flash>, # parts = 6
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#: name size offset mask_flags
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0: kernel 0x00200000 0x00000000 0
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1: dtb 0x00040000 0x00200000 0
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2: root 0x00200000 0x00240000 0
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3: user 0x01ac0000 0x00440000 0
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4: env 0x00080000 0x01f00000 0
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5: u-boot 0x00080000 0x01f80000 0
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active partition: nor0,0 - (kernel) 0x00200000 @ 0x00000000
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defaults:
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mtdids : nor0=1fc000000.nor_flash
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mtdparts: mtdparts=1fc000000.nor_flash:2m(kernel),256k(dtb),2m(root),27392k(user),512k(env),512k(u-boot)
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=> ubi part root
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Creating 1 MTD partitions on "nor0":
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0x000000240000-0x000000440000 : "mtd=2"
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UBI: attaching mtd1 to ubi0
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UBI: physical eraseblock size: 262144 bytes (256 KiB)
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UBI: logical eraseblock size: 262016 bytes
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UBI: smallest flash I/O unit: 1
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UBI: VID header offset: 64 (aligned 64)
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UBI: data offset: 128
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UBI: attached mtd1 to ubi0
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UBI: MTD device name: "mtd=2"
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UBI: MTD device size: 2 MiB
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UBI: number of good PEBs: 8
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UBI: number of bad PEBs: 0
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UBI: max. allowed volumes: 128
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UBI: wear-leveling threshold: 4096
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UBI: number of internal volumes: 1
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UBI: number of user volumes: 1
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UBI: available PEBs: 0
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UBI: total number of reserved PEBs: 8
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UBI: number of PEBs reserved for bad PEB handling: 0
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UBI: max/mean erase counter: 2/1
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Now that the UBI device is attached, this device can be modified
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using the following commands:
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ubi info Display volume and ubi layout information
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ubi createvol Create UBI volume on UBI device
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ubi removevol Remove UBI volume from UBI device
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ubi read Read data from UBI volume to memory
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ubi write Write data from memory to UBI volume
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ubi write.part Write data from memory to UBI volume, in parts
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Here a few examples on the usage:
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=> ubi create testvol
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Creating dynamic volume testvol of size 1048064
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=> ubi info l
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UBI: volume information dump:
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UBI: vol_id 0
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UBI: reserved_pebs 4
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UBI: alignment 1
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UBI: data_pad 0
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UBI: vol_type 3
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UBI: name_len 7
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UBI: usable_leb_size 262016
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UBI: used_ebs 4
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UBI: used_bytes 1048064
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UBI: last_eb_bytes 262016
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UBI: corrupted 0
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UBI: upd_marker 0
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UBI: name testvol
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UBI: volume information dump:
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UBI: vol_id 2147479551
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UBI: reserved_pebs 2
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UBI: alignment 1
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UBI: data_pad 0
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UBI: vol_type 3
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UBI: name_len 13
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UBI: usable_leb_size 262016
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UBI: used_ebs 2
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UBI: used_bytes 524032
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UBI: last_eb_bytes 2
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UBI: corrupted 0
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UBI: upd_marker 0
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UBI: name layout volume
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=> ubi info
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UBI: MTD device name: "mtd=2"
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UBI: MTD device size: 2 MiB
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UBI: physical eraseblock size: 262144 bytes (256 KiB)
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UBI: logical eraseblock size: 262016 bytes
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UBI: number of good PEBs: 8
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UBI: number of bad PEBs: 0
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UBI: smallest flash I/O unit: 1
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UBI: VID header offset: 64 (aligned 64)
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UBI: data offset: 128
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UBI: max. allowed volumes: 128
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UBI: wear-leveling threshold: 4096
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UBI: number of internal volumes: 1
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UBI: number of user volumes: 1
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UBI: available PEBs: 0
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UBI: total number of reserved PEBs: 8
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UBI: number of PEBs reserved for bad PEB handling: 0
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UBI: max/mean erase counter: 4/1
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=> ubi write 800000 testvol 80000
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Volume "testvol" found at volume id 0
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=> ubi read 900000 testvol 80000
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Volume testvol found at volume id 0
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read 524288 bytes from volume 0 to 900000(buf address)
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=> cmp.b 800000 900000 80000
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Total of 524288 bytes were the same
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Next, the ubifsmount command allows you to access filesystems on the
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UBI partition which has been attached with the ubi part command:
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=> help ubifsmount
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ubifsmount - mount UBIFS volume
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Usage:
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ubifsmount <volume-name>
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- mount 'volume-name' volume
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For example:
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=> ubifsmount ubi0:recovery
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UBIFS: mounted UBI device 0, volume 0, name "recovery"
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UBIFS: mounted read-only
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UBIFS: file system size: 46473216 bytes (45384 KiB, 44 MiB, 366 LEBs)
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UBIFS: journal size: 6348800 bytes (6200 KiB, 6 MiB, 50 LEBs)
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UBIFS: media format: w4/r0 (latest is w4/r0)
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UBIFS: default compressor: LZO
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UBIFS: reserved for root: 0 bytes (0 KiB)
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Note that unlike Linux, U-Boot can only have one active UBI partition
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at a time, which can be referred to as ubi0, and must be supplied along
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with the name of the filesystem you are mounting.
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Once a UBI filesystem has been mounted, the ubifsls command allows you
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to list the contents of a directory in the filesystem:
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=> help ubifsls
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ubifsls - list files in a directory
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Usage:
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ubifsls [directory]
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- list files in a 'directory' (default '/')
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For example:
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=> ubifsls
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17442 Thu Jan 01 02:57:38 1970 imx28-evk.dtb
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2998146 Thu Jan 01 02:57:43 1970 zImage
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And the ubifsload command allows you to load a file from a UBI
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filesystem:
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=> help ubifsload
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ubifsload - load file from an UBIFS filesystem
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Usage:
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ubifsload <addr> <filename> [bytes]
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- load file 'filename' to address 'addr'
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For example:
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=> ubifsload ${loadaddr} zImage
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Loading file 'zImage' to addr 0x42000000 with size 2998146 (0x002dbf82)...
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Done
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Finally, you can unmount the UBI filesystem with the ubifsumount
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command:
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=> help ubifsumount
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ubifsumount - unmount UBIFS volume
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Usage:
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ubifsumount - unmount current volume
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For example:
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=> ubifsumount
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Unmounting UBIFS volume recovery!
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