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After installing Ubuntu as a second system on my Macbook following this tutorial https://www.maketecheasier.com/install-dual-boot-ubuntu-mac/ everything was just working fine and I was able to boot into either macOS or Ubuntu via rEFInd.

Then I resized macOS's partition again to create a partition to share data between macOS and Ubuntu. Unfortunately rEFInd does not find the macOS Partition anymore and I am therefore not able to boot into macOS.

My partitions look like this at the moment:

sda             489,1G                              
├─sda1 vfat       200M /boot/efi                    EFI
├─sda2 apfs       351G                              
├─sda3 swap       3,7G [SWAP]                       
├─sda4 ext4     115,5G /                            
└─sda5 vfat      18,6G                              SHARE

Any help would be highly appreciated.

Edits:

  • I used the builtin Mac Program to resize the partition

  • Output of sudo gdisk -l /dev/sda:

    GPT fdisk (gdisk) version 1.0.5

 Partition table scan:
   MBR: hybrid
   BSD: not present
   APM: not present
   GPT: present

 Found valid GPT with hybrid MBR; using GPT.
 Disk /dev/sda: 1025610768 sectors, 489.0 GiB
 Model: Crucial_CT525MX3
 Sector size (logical/physical): 512/512 bytes
 Disk identifier (GUID): 2AA86904-096B-4D1C-9DD0-3C8B1FD84B37
 Partition table holds up to 128 entries
 Main partition table begins at sector 2 and ends at sector 33
 First usable sector is 34, last usable sector is 1025610734
 Partitions will be aligned on 8-sector boundaries
 Total free space is 1653 sectors (826.5 KiB)

 Number  Start (sector)    End (sector)  Size       Code  Name
    1              40          409639   200.0 MiB   EF00  EFI System Partition
    2          409640       736548223   351.0 GiB   FFFF  tichan
    3       775612416       783423487   3.7 GiB     8200  
    4       783423488      1025609727   115.5 GiB   8300  
    5       736548864       775612415   18.6 GiB    0700
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  • What tool did you use to resize the macOS partition? Also, edit your question and add the output from the command sudo gdisk -l /dev/sda.
    – David Anderson
    Aug 6, 2020 at 14:46
  • Edited information :)
    – Uncle Cuppa
    Aug 7, 2020 at 6:48

1 Answer 1

Reset to default
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The type GUID for partition 2 of /dev/sda is wrong. The commands below will correct the problem. Enter the commands in an Ubuntu terminal window.

sudo gdisk /dev/sda
t
2
AF0A
w
y

Note: I realize the gdisk output shows hybrid partitioning. However, both macOS and Ubuntu should ignore the 2nd, 3rd and 4th entries in the MBR partition table.

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3
  • Just did that, but now running efibootmgr, does not show me MacOS or rEFInd anymore. How am I now able to boot into macOS?
    – Uncle Cuppa
    Aug 7, 2020 at 10:12
  • The efibootmgr functionality is not very compatible with how a Mac operates. If you want to choose macOS as the default to boot from Ubuntu, I would suggest doing this by modifying the rEFInd configuration instead of using efibootmgr. You can also use the Mac Startup Manager to choose to boot macOS.
    – David Anderson
    Aug 7, 2020 at 17:52
  • 1
    Faced the same issue after growing the APFS partition using Disk Utility in MacOS Recovery Mode. Fixing the partition type got refind to detect the partition and boot into MacOS again. Changing the partition type should not affect efibootmgr output afaik.
    – Nemo
    Mar 3, 2021 at 11:18

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