I have a MacBook Pro (mid-2015) where I set up a dual boot system with MacOS and Windows 10, which I have been happily running for over 3 years now. At the time I was going to try to triple boot with Ubuntu 16.04 but I ran out of space on my Windows (Bootcamp) partition where I was going to install Ubuntu. After reading a number of articles, I decided to set up Ubuntu on a USB Flash drive following the valuable instructions of Tim Richardson to uncheck the EFI boot and esp flags from my internal drive so the installer could only see and load EFI on my USB flash drive. It looks like it worked! I have a USB Flash drive which I can plug into an old MacBook Pro (2008) and bring up Ubuntu 20.04 but it has royally screwed up the boot loader on my MacBook Pro (mid-2015) which I wanted to triple boot from. Here are the Before and After snapshots of my system:
Before
Ricks-MacBook-Pro:~ rickmaxxx$ diskutil list
/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *251.0 GB disk0
1: EFI EFI 209.7 MB disk0s1
2: Apple_APFS Container disk1 165.0 GB disk0s2
3: Microsoft Basic Data BOOTCAMP 84.9 GB disk0s3
4: Windows Recovery 897.6 MB disk0s4
/dev/disk1 (synthesized):
#: TYPE NAME SIZE IDENTIFIER
0: APFS Container Scheme - +165.0 GB disk1
Physical Store disk0s2
1: APFS Volume Macintosh HD 88.3 GB disk1s1
2: APFS Volume Preboot 46.6 MB disk1s2
3: APFS Volume Recovery 510.5 MB disk1s3
4: APFS Volume VM 1.1 GB disk1s4
Ricks-MacBook-Pro:~ rickmaxxx$ sudo gpt -r show /dev/disk0
Password:
start size index contents
0 1 PMBR
1 1 Pri GPT header
2 32 Pri GPT table
34 6
40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
409640 322289624 2 GPT part - 7C3457EF-0000-11AA-AA11-00306543ECAC
322699264 165778528 3 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
488477792 928
488478720 1753088 4 GPT part - DE94BBA4-06D1-4D40-A16A-BFD50179D6AC
490231808 2911
490234719 32 Sec GPT table
490234751 1 Sec GPT header
Ricks-MacBook-Pro:~ rickmaxxx$ sudo fdisk /dev/disk0
Disk: /dev/disk0 geometry: 30515/255/63 [490234752 sectors]
Signature: 0xAA55
Starting Ending
#: id cyl hd sec - cyl hd sec [ start - size]
------------------------------------------------------------------------
1: EE 1023 254 63 - 1023 254 63 [ 1 - 490234751] <Unknown ID>
2: 00 0 0 0 - 0 0 0 [ 0 - 0] unused
3: 00 0 0 0 - 0 0 0 [ 0 - 0] unused
4: 00 0 0 0 - 0 0 0 [ 0 - 0] unused
Ricks-MacBook-Pro:~ rickmaxxx$
After
Ricks-MacBook-Pro:~ rickmaxxx$ diskutil list
/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *251.0 GB disk0
1: EFI EFI 209.7 MB disk0s1
2: Apple_APFS Container disk1 165.0 GB disk0s2
3: Microsoft Basic Data BOOTCAMP 84.9 GB disk0s3
4: Windows Recovery 897.6 MB disk0s4
/dev/disk1 (synthesized):
#: TYPE NAME SIZE IDENTIFIER
0: APFS Container Scheme - +165.0 GB disk1
Physical Store disk0s2
1: APFS Volume Macintosh HD 90.9 GB disk1s1
2: APFS Volume Preboot 46.6 MB disk1s2
3: APFS Volume Recovery 510.5 MB disk1s3
4: APFS Volume VM 1.1 GB disk1s4
Ricks-MacBook-Pro:~ rickmaxxx$ sudo gpt -r show /dev/disk0
Password:
gpt show: /dev/disk0: Suspicious MBR at sector 0
start size index contents
0 1 MBR
1 1 Pri GPT header
2 32 Pri GPT table
34 6
40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
409640 322289624 2 GPT part - 7C3457EF-0000-11AA-AA11-00306543ECAC
322699264 165778528 3 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
488477792 928
488478720 1753088 4 GPT part - DE94BBA4-06D1-4D40-A16A-BFD50179D6AC
490231808 2911
490234719 32 Sec GPT table
490234751 1 Sec GPT header
Ricks-MacBook-Pro:~ rickmaxxx$ sudo fdisk /dev/disk0
Disk: /dev/disk0 geometry: 30515/255/63 [490234752 sectors]
Signature: 0xAA55
Starting Ending
#: id cyl hd sec - cyl hd sec [ start - size]
------------------------------------------------------------------------
1: EE 0 0 1 - 1023 254 63 [ 1 - 409639] <Unknown ID>
*2: DA 1023 254 63 - 1023 254 63 [ 409640 - 322289624] <Unknown ID>
3: 07 1023 254 63 - 1023 254 63 [ 322699264 - 165778528] HPFS/QNX/AUX
4: 07 1023 254 63 - 1023 254 63 [ 488478720 - 1753088] HPFS/QNX/AUX
Ricks-MacBook-Pro:~ rickmaxxx$
Note the message "gpt show: /dev/disk0: Suspicious MBR at sector 0"
So, the major consequence of all this is that I can no longer boot into Windows (Bootcamp). All I get is a dark screen. The MacOS system seems to be working fine but sector 0 used to be PMBR and now it is MBR. Prior to this I installed rEFInd successfully and was quite happy with the results thinking that Linux Ubuntu would happily work alongside it to allow me to triple boot.
However, when I start my MacBook Pro with the USB Flash Drive installed, it goes directly into Ubuntu without any appearance of rEFInd. Everything in Ubuntu works as expected.
Alternatively, when I start my MacBook Pro by holding down the "option" key to select Ubuntu, I get the following cryptic message:
APFSStart:1555: Mounting with apfs_efi_osx-945.275.9
efi_fusion_pairing:668: Container 06a8e9fd-ae73-4c94-92de-a80e6c2e6099
efi_fusion_pairing:673: fusion uuid: 00000000-0000-0000-0000-000000000000
efi_container_create:972: Volume attached is internal
nx_kernel_mount:1473: : checkpoint search: largest xid 790302, best xid 790302 @ 135
er_state_obj_get_for_recovery:4214: No ER state object for volume Preboot
- rolling is not happening, nothing to recover.
er_state_obj_get_for_recovery:4214: No ER state object for volume Recovery
- rolling is not happening, nothing to recover.
er_state_obj_get_for_recovery:4214: No ER state object for volume VM
- rolling is not happening, nothing to recover.
System BootOrder not found. Initializing defaults.
When I boot into MacOS and open Disk Utility to look at Bootcamp, everything seems to still be there, but I'm not sure what I need to fix to get me access. I will start poring over any and all articles to do with Boot Loader but if anyone has any ideas it would be greatly appreciated. As a last resort I will try to recover using Carbon Copy Cloner but I'm not sure if it will bring back my Boot Loader sequence. Thanks in advance for any and all suggestions.
