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