overlay-sama5d3/scripts/disk_layout.json

{
  "parent": "legacy_disk_layout.json",
  "layouts":{
    "common":[
      {
        "num": "metadata",
        "hybrid_mbr": true
      },
      {
        "num": 5,
        "size":"400 MiB",
        "fs_size":"350 MiB"
      },
      {
        "num": 3,
        "size":"400 MiB",
        "fs_size":"350 MiB"
      }
    ]
  }
}