d-i partman-auto/disk string /dev/sda
d-i partman-auto/method string regular
d-i partman-lvm/device_remove_lvm boolean true
d-i partman-md/device_remove_md boolean true
d-i partman-lvm/confirm boolean true
d-i partman/alignment string "optimal"
d-i partman-auto/expert_recipe string
      boot-root ::
              64 512 300% linux-swap
                      $primary{ }
                      method{ swap } format{ }
              .
              500 10000 1000000000 ext4
                      $primary{ } $bootable{ }
                      method{ format } format{ }
                      use_filesystem{ } filesystem{ ext4 }
                      mountpoint{ / }
              .
d-i partman/confirm_write_new_label boolean true
d-i partman/choose_partition select finish
d-i partman/confirm boolean true
d-i partman/confirm_nooverwrite boolean true

boot-root ::
          32768 65536 1000000000 ext4
                  $primary{ } $bootable{ }
                  method{ format } format{ }
                  use_filesystem{ } filesystem{ ext4 }
                  mountpoint{ / }
          .
          16384 16384 65536 linux-swap
                  $primary{ }
                  method{ swap } format{ }
          .

d-i partman-basicfilesystems/choose_label string gpt
d-i partman-basicfilesystems/default_label string gpt
d-i partman-partitioning/choose_label string gpt
d-i partman-partitioning/default_label string gpt
d-i partman/choose_label string gpt
d-i partman/default_label string gpt

1 1 1 free
        $primary{}
        $bios_boot{}
        method{ biosgrub }
    .

538 538 1075 free
        $iflabel{ gpt }
        $reusemethod{ }
        method{ efi }
        format{ } .

d-i partman-auto/expert_recipe string
    boot-root ::
        1 1 -1 ext4
            $primary{ } $bootable{ }
            method{ format } format{ }
            use_filesystem{ } filesystem{ ext4 }
            mountpoint{ / }
        .
        65536 65536 65536 linux-swap
            $primary{ }
            method{ swap } format { }
        .