{
  "_comment": "See README_disk_layout",

  "metadata":{
    "block_size": 512,
    "fs_block_size": 4096
  },
  "layouts":{
    "_comment": "base is the standard layout template. Also used for installs.",
    "base": [
      {
        "_comment": "Reserve space for RW firmware. Only used on some boards.",
        "num": 11,
        "label":"RWFW",
        "type":"firmware",
        "size":"8 MiB"
      },
      {
        "_comment": "Unused partition, reserved for software slot C.",
        "num": 6,
        "label":"KERN-C",
        "type":"kernel",
        "blocks":"1"
      },
      {
        "_comment": "Unused partition, reserved for software slot C.",
        "num": 7,
        "label":"ROOT-C",
        "type":"rootfs",
        "blocks":"1"
      },
      {
        "_comment": "Unused partition, reserved for future changes.",
        "num": 9,
        "type":"reserved",
        "label":"reserved",
        "blocks":"1"
      },
      {
        "_comment": "Unused partition, reserved for future changes.",
        "num": 10,
        "type":"reserved",
        "label":"reserved",
        "blocks":"1"
      },
      {
        "_comment": "Pad out so Kernel A starts on a 4096 block boundry for",
        "_comment": " performance. This is especially important on Daisy.",
        "type":"blank",
        "size":"2014 KiB"
      },
      {
        "_comment": "Kernel for Slot A, no file system.",
        "num": 2,
        "label":"KERN-A",
        "type":"kernel",
        "size":"16 MiB"
      },
      {
        "_comment": "Kernel for Slot B, no file system.",
        "num": 4,
        "label":"KERN-B",
        "type":"kernel",
        "size":"16 MiB"
      },
      {
        "_comment": "Board specific files, mostly unused.",
        "num": 8,
        "label":"OEM",
        "type":"data",
        "fs_format":"ext4",
        "size":"16 MiB",
        "uuid": "random"
      },
      {
        "_comment": "Pad out, but not sure why.",
        "type":"blank",
        "size":"64 MiB"
      },
      {
        "_comment": "Used for Legacy Bios, and EFI Bios, not ChromeOS hardware",
        "num": 12,
        "label":"EFI-SYSTEM",
        "type":"efi",
        "fs_format":"vfat",
        "size":"16 MiB",
        "uuid": "clear"
      },
      {
        "_comment": "Slot B rootfs. Must match Root A in side for normal",
        "_comment": "updates. Will contain copy of Root A after install, and",
        "_comment": "contain new rootfs's after runtime updates.",
        "num": 5,
        "label":"ROOT-B",
        "type":"rootfs",
        "size":"2048 MiB"
      },
      {
        "_comment": "Slot A rootfs. Rootfs + extras must fit.",
        "_comment": "FS size + Verity (64 * FS blocks) + Boot Cache (200M).",
        "_comment": "Make sure that other layouts still has room for the ",
        "_comment": "extras, should you increase FS size",
        "_comment": "",
        "_comment": "Note that updates will fail if the rootfs size",
        "_comment": "shrinks. (crbug.com/192136)",
        "_comment": "",
        "_comment": "Changes to the offset of this partition may require",
        "_comment": "changes in cros-signing/security_test_baselines/",
        "_comment": "ensure_secure_kernelparams.config to allow secure boot.",
        "num": 3,
        "label":"ROOT-A",
        "type":"rootfs",
        "fs_format":"ext2",
        "size":"2048 MiB",
        "fs_size":"1224 MiB",
        "uuid": "clear"
      },
      {
        "_comment": "User data, fills all remaining space on drive.",
        "num": 1,
        "label":"STATE",
        "type":"data",
        "fs_format":"ext4",
        "size":"1024 MiB",
        "features":["expand"],
        "uuid": "random"
      }
    ],
    "_comment": "Used for bootable USB installs (not recovery).",
    "usb": [
      {
        "_comment": "Shrunken rootfs partition to support smaller USB sticks.",
        "_comment": "installation will expand this to size from base.",
        "num": 3,
        "size":"1290 MiB"
      },
      {
        "_comment": "Slot B rootfs, unused on USB, but pad to 2M.",
        "_comment": "installation will expand this to size from base.",
        "num": 5,
        "size":"2 MiB"
      }
    ],
    "_comment": "Used for factory install images.",
    "factory_install": [
      {
        "num": 1,
        "size":"140 MiB"
      },
      {
        "num": 3,
        "size":"420 MiB",
        "fs_size":"400 MiB"
      },
      {
        "num": 5,
        "size":"2 MiB"
      },
      {
        "num": 12,
        "size":"32 MiB"
      }
    ],
    "_comment": "Used for recovery images.",
    "recovery": [
      {
        "_comment": "Stateful on recovery is dynamically resized larger.",
        "num": 1,
        "size":"2 MiB"
      },
      {
        "_comment": "Shrunken rootfs partition to support smaller USB sticks,",
        "_comment": "and smaller recovery downloads.",
        "_comment": "Installation will expand this to size from base.",
        "_comment": "The offset to the beginning of this partition, and the FS",
        "_comment": "size must match base exactly to allow secure boot.",
        "num": 3,
        "size":"1290 MiB"
      },
      {
        "_comment": "Slot B rootfs, unused on USB, but pad to 2M.",
        "_comment": "installation will expand this to size from base.",
        "num": 5,
        "size":"2 MiB"
      }
    ],
    "_comment": "Larger rootfs, suitable for development with symbols, etc.",
    "_comment": "Cannot apply updates when running from USB (no slot B).",
    "2gb-rootfs": [
      {
        "_comment": "Will be shrunk to size from base on install.",
        "num": 3,
        "size":"2048 MiB",
        "fs_size":"2000 MiB"
      },
      {
        "_comment": "Will be grown to size from base on install.",
        "num": 5,
        "size":"2 MiB"
      }
    ],
    "_comment": "Larger rootfs, suitable for development with symbols, etc.",
    "_comment": "CAN apply updates when running from USB.",
    "2gb-rootfs-updatable": [
      {
        "num": 1,
        "size":"3072 MiB"
      },
      {
        "_comment": "The partition size matches base, so it's installable.",
        "num": 3,
        "size":"2048 MiB",
        "fs_size":"2000 MiB"
      },
      {
        "_comment": "The partition size matches base, so it's installable.",
        "num": 5,
        "size":"2048 MiB"
      }
    ],
    "_comment": "Very large rootfs, suitable for development with symbols,",
    "_comment": "etc. Cannot apply updates when running from USB (no slot B)",
    "4gb-rootfs": [
      {
        "_comment": "This partition is larger than the base partition, so the",
        "_comment": "installer will corrupt the disk during installation.",
        "num": 3,
        "size":"4096 MiB",
        "fs_size":"4000 MiB"
      },
      {
        "num": 5,
        "size":"2 MiB"
      }
    ]
  }
}