Carbon Copy Cloner and SuperDuper! ignore EFI partitions #

When making a bootable clone with Carbon Copy Cloner or SuperDuper!, EFI partitions are skipped, since they aren't needed for macOS boot disks:

Though modern Macs support ... EFI booting in order to maintain compatibility with running non-Apple operating system[s] on their hardware, they do NOT need the EFI partition in order to boot [m]acOS. Because of this, the disk clone utilities do not copy the contents of the secondary EFI partition from one drive to another when doing their job.

However, this is problematic when cloning boot disks like the one produced by Ben Sova's Patched-Sur, which depend on the EFI partition for critical functionality.

Here's how to clone the EFI partition as well:

  1. Partition (GUID) and format (HFS+) the target disk

  2. Use Carbon Copy Cloner to clone the source disk to the target disk

  3. Mount the source and target EFI partitions

    % diskutil list
    /dev/disk2 (external, physical):
       #:                       TYPE NAME                    SIZE       IDENTIFIER
       0:      GUID_partition_scheme                        *126.7 GB   disk2
       1:                        EFI ⁨EFI⁩                     209.7 MB   disk2s1
       2:                  Apple_HFS ⁨Install macOS Big Sur⁩   126.4 GB   disk2s2
    /dev/disk3 (external, physical):
       #:                       TYPE NAME                    SIZE       IDENTIFIER
       0:      GUID_partition_scheme                        *61.5 GB    disk3
       1:                        EFI ⁨EFI⁩                     209.7 MB   disk3s1
       2:                  Apple_HFS ⁨SanDisk                 61.2 GB    disk3s2
    % sudo diskutil mount disk2s1
    Volume EFI on disk2s1 mounted
    % sudo diskutil mount disk3s1
    Volume EFI on disk3s1 mounted
  4. Copy the EFI folder from the source disk's EFI partition to the target disk's empty EFI partition via Finder or Terminal



/mac | Apr 26, 2021

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