What does macOS need?

To understand where these sections come from, you need to understand what macOS is looking for in a disk drive for it to install "properly". macOS put some restrictions on the size and the possibility to even format a partition as HFS+ if some requirements are not fulfilled.

macOS looks for:

• a GPT formatted disk

• a EFI partition:

  • FAT32 formatted (not that it matters for it)

  • flagged as EFI System Partition (hex: EF00 in gdisk)

  • is 200MB at least

  • in the same disk where macOS should be installed.

• 60GB of free space

If any of these are in your target disk, you're good to go, if not, that's the point of this guide.