2 Explained why the fake partition on the protective MBR may need to be set active.
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  • grub itself does not care about boot flags.
  • An EFI System partition is distinguished by its GUID type C12A7328-F81F-11D2-BA4B-00A0C93EC93B, not by a boot flag. Yes, this partition needs to be formatted FAT32. Not all FAT32 partitions are EFI System partitions, only one of them, and that one, if present, is small and has a special purpose. On a computer which boots through BIOS or BIOS emulation you don't need it. You may want to create an EFI System partition (about 300 MB, in parted say mkpart fat32 and set boot on), for the case that some day the disk will be moved to a computer with UEFI.
  • Your /boot partition does not need a boot flag and should not have one.
  • However, the sole partition in the protective MBR may need a (legacy) boot flag if the firmware of your computer wants it. (Some BIOSes won't boot a hard disk unless it has a primary MBR partition with the active flag set.)
  • Not all computers support booting from GPT disks under BIOS or BIOS emulation. In fact, this is explicitly unsupported. It usually works, though.
  • grub itself does not care about boot flags.
  • An EFI System partition is distinguished by its GUID type C12A7328-F81F-11D2-BA4B-00A0C93EC93B, not by a boot flag. Yes, this partition needs to be formatted FAT32. Not all FAT32 partitions are EFI System partitions, only one of them, and that one, if present, is small and has a special purpose. On a computer which boots through BIOS or BIOS emulation you don't need it. You may want to create an EFI System partition (about 300 MB, in parted say mkpart fat32 and set boot on), for the case that some day the disk will be moved to a computer with UEFI.
  • Your /boot partition does not need a boot flag and should not have one.
  • However, the sole partition in the protective MBR may need a (legacy) boot flag if the firmware of your computer wants it.
  • Not all computers support booting from GPT disks under BIOS or BIOS emulation. In fact, this is explicitly unsupported. It usually works, though.
  • grub itself does not care about boot flags.
  • An EFI System partition is distinguished by its GUID type C12A7328-F81F-11D2-BA4B-00A0C93EC93B, not by a boot flag. Yes, this partition needs to be formatted FAT32. Not all FAT32 partitions are EFI System partitions, only one of them, and that one, if present, is small and has a special purpose. On a computer which boots through BIOS or BIOS emulation you don't need it. You may want to create an EFI System partition (about 300 MB, in parted say mkpart fat32 and set boot on), for the case that some day the disk will be moved to a computer with UEFI.
  • Your /boot partition does not need a boot flag and should not have one.
  • However, the sole partition in the protective MBR may need a (legacy) boot flag if the firmware of your computer wants it. (Some BIOSes won't boot a hard disk unless it has a primary MBR partition with the active flag set.)
  • Not all computers support booting from GPT disks under BIOS or BIOS emulation. In fact, this is explicitly unsupported. It usually works, though.
1
source | link

  • grub itself does not care about boot flags.
  • An EFI System partition is distinguished by its GUID type C12A7328-F81F-11D2-BA4B-00A0C93EC93B, not by a boot flag. Yes, this partition needs to be formatted FAT32. Not all FAT32 partitions are EFI System partitions, only one of them, and that one, if present, is small and has a special purpose. On a computer which boots through BIOS or BIOS emulation you don't need it. You may want to create an EFI System partition (about 300 MB, in parted say mkpart fat32 and set boot on), for the case that some day the disk will be moved to a computer with UEFI.
  • Your /boot partition does not need a boot flag and should not have one.
  • However, the sole partition in the protective MBR may need a (legacy) boot flag if the firmware of your computer wants it.
  • Not all computers support booting from GPT disks under BIOS or BIOS emulation. In fact, this is explicitly unsupported. It usually works, though.