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Iyassou Author

Level 1

0 points

GPT help

https://discussions.apple.com/thread/4144252?answerId=26125763022#26125763022

Output of sudo fdisk /dev/rdisk0 :

Disk: /dev/rdisk0

geometry: 60801/255/63 [976773168 sectors]

Signature: 0xAA55

Starting Ending

#: id cyl hd sec - cyl hd sec [ start - size]

------------------------------------------------------------------------

1: EE 1023 254 63 - 1023 254 63 [ 1 - 409639] <Unknown ID>

2: 07 1023 254 63 - 1023 254 63 [ 409640 - 469338128] HPFS/QNX/AUX

3: AB 1023 254 63 - 1023 254 63 [ 469747768 - 1269536] Darwin Boot

4: 07 1023 254 63 - 1023 254 63 [ 471017472 - 76855296] HPFS/QNX/AUX

I am using GPT fdisk (or gdisk).

I don't remember all that I've tried to do, but the changes that I had made were: changing the 4th partition's id to 07 (then because of a confusion, the 2nd partition's id to 07). That's it.

MacBook Pro, Mac OS X (10.7)

Posted on Jun 15, 2014 10:24 AM

37 replies

Iyassou Author

Level 1

0 points

Jun 16, 2014 5:41 AM in response to Loner T

I can't boot into anything. My computer is shut down and I'm replying from my phone.

Loner T

Level 9

59,513 points

Jun 16, 2014 5:49 AM in response to Iyassou

Iyassou wrote:

I can't boot into anything. My computer is shut down and I'm replying from my phone.

Do you have access to a second MAC computer?

Do you have an external CD/DVD?

Iyassou Author

Level 1

0 points

Jul 4, 2014 9:39 AM in response to Loner T

Hi, I found another mac. Here's the output of sudo fdisk /dev/disk1:

Disk: /dev/disk1 geometry: 60801/255/63 [976773168 sectors]

Signature: 0xAA55

Starting Ending

#: id cyl hd sec - cyl hd sec [ start - size]

------------------------------------------------------------------------

1: EE 1023 254 63 - 1023 254 63 [ 1 - 409639] <Unknown ID>

2: AF 1023 254 63 - 1023 254 63 [ 409640 - 469338128] HFS+

3: AB 1023 254 63 - 1023 254 63 [ 469747768 - 1269536] Darwin Boot

*4: 07 1023 254 63 - 1023 254 63 [ 471017472 - 352045056] HPFS/QNX/AUX

Loner T

Level 9

59,513 points

Jul 4, 2014 10:11 AM in response to Iyassou

Can you also post the GPT for this disk? Just need to ensure they are both in sync.

Iyassou Author

Level 1

0 points

Jul 4, 2014 10:20 AM in response to Loner T

And how do I do that? Sorry if this was a simple question

Loner T

Level 9

59,513 points

Jul 4, 2014 10:28 AM in response to Iyassou

sudo gpt -vv -r show /dev/disk1

The MBR looks correct. MAC OS X not booting is strange!

Iyassou Author

Level 1

0 points

Jul 4, 2014 10:31 AM in response to Loner T

Here's the output of sudo gpt -vv -r show /dev/disk1 :

gpt show: /dev/disk1: mediasize=500107862016; sectorsize=512; blocks=976773168

gpt show: /dev/disk1: Suspicious MBR at sector 0

gpt show: /dev/disk1: Pri GPT at sector 1

gpt show: /dev/disk1: Sec GPT at sector 976773167

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 469338128 2 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

469747768 1269536 3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

471017304 168

471017472 352045056 4 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

823062528 153710607

976773135 32 Sec GPT table

976773167 1 Sec GPT header

Loner T

Level 9

59,513 points

Jul 4, 2014 11:47 AM in response to Iyassou

This is strange, because they both match.

One possibility is that bless information was lost when Partition 2 was changed from '07' to 'AF'. Can you run the following command.

The "Macintosh\ HD" string in the following command needs to be replaced with the volume name that you can see when you run diskutil list command for /dev/disk1. Sample output from my machine is shown below.

diskutil list

/dev/disk0

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_HFS Macintosh HD 743.7 GB disk0s2

3: Apple_Boot Recovery HD 650.0 MB disk0s3

4: Microsoft Basic Data BOOTCAMP 256.0 GB disk0s4

sudo bless --info /Volumes/Macintosh\ HD/System/Library/CoreServices/

finderinfo[0]: 45 => Blessed System Folder is /System/Library/CoreServices

finderinfo[1]: 1478210 => Blessed System File is /System/Library/CoreServices/boot.efi

finderinfo[2]: 0 => Open-folder linked list empty

finderinfo[3]: 0 => No alternate OS blessed file/folder

finderinfo[4]: 0 => Unused field unset

finderinfo[5]: 45 => OS X blessed folder is /System/Library/CoreServices

64-bit VSDB volume id: 0x3EE7659409EF64D1

Iyassou Author

Level 1

0 points

Jul 4, 2014 12:13 PM in response to Loner T

Output of diskutil list :

/dev/disk0

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *500.3 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_HFS Macintosh HD 499.4 GB disk0s2

3: Apple_Boot Recovery HD 650.0 MB disk0s3

/dev/disk1

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *500.1 GB disk1

1: EFI EFI 209.7 MB disk1s1

2: Microsoft Basic Data 240.3 GB disk1s2

3: Apple_Boot Recovery HD 650.0 MB disk1s3

4: Microsoft Basic Data 180.2 GB disk1s4

So should I write : sudo bless --info Microsoft Basic Data ? I think that I am wrong here...

Loner T

Level 9

59,513 points

Jul 4, 2014 12:32 PM in response to Iyassou

Bless is OSX specific. Do not use it on Bootcamp volume. The last string in this line (called the PartitionType GUID)

409640 469338128 2 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

is incorrect. It should

409640 1452530904 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC

OS X will not recognize this and boot from it. Fdisk and GPT are two separate entities. the '07' to 'AF' was corrected in MBR (via fdisk), but the GPT needs to be corrected via gdisk.

This is what it should look like...

Partition number (1-4): 2

Partition GUID code: 48465300-0000-11AA-AA11-00306543ECAC (Apple HFS/HFS+)

Partition unique GUID: 98D8DC3F-F7F8-41A2-B5AA-6FBFC53694BB

First sector: 409640 (at 200.0 MiB)

Last sector: 1452940543 (at 692.8 GiB)

Partition size: 1452530904 sectors (692.6 GiB)

Attribute flags: 0000000000000000

Partition name: 'Customer'

Loner T

Level 9

59,513 points

Jul 4, 2014 12:46 PM in response to Iyassou

I suggest you read this first - http://www.rodsbooks.com/gdisk/repairing.html before an attempt is made to fix the GPT.

Need to ensure the commands I give you do not cause further damage.

Loner T

Level 9

59,513 points

Jul 4, 2014 1:09 PM in response to Iyassou

Can you run the following commands? These do not change the GPT in any way.

sudo gdisk /dev/disk1

Here is what I did on my system.

sudo gdisk /dev/disk0

Password:

GPT fdisk (gdisk) version 0.8.9

Warning: Devices opened with shared lock will not have their

partition table automatically reloaded!

Partition table scan:

MBR: hybrid

BSD: not present

APM: not present

GPT: present

Found valid GPT with hybrid MBR; using GPT.

Command (? for help): p

Disk /dev/disk0: 1954210120 sectors, 931.8 GiB

Logical sector size: 512 bytes

Disk identifier (GUID): 6ED0C429-00D1-4759-B50E-04B6FB80D0E3

Partition table holds up to 128 entries

First usable sector is 34, last usable sector is 1954210086

Partitions will be aligned on 8-sector boundaries

Total free space is 1293 sectors (646.5 KiB)

Number Start (sector) End (sector) Size Code Name

1 40 409639 200.0 MiB EF00 EFI System Partition

2 409640 1452940543 692.6 GiB AF00 Customer

3 1452940544 1454210079 619.9 MiB AB00 Recovery HD

4 1454211072 1954209791 238.4 GiB 0700 BOOTCAMP

Command (? for help): i

Partition number (1-4): 2

Partition GUID code: 48465300-0000-11AA-AA11-00306543ECAC (Apple HFS/HFS+)

Partition unique GUID: 98D8DC3F-F7F8-41A2-B5AA-6FBFC53694BB

First sector: 409640 (at 200.0 MiB)

Last sector: 1452940543 (at 692.8 GiB)

Partition size: 1452530904 sectors (692.6 GiB)

Attribute flags: 0000000000000000

Partition name: 'Customer'

Command (? for help): q

Iyassou Author

Level 1

0 points

Jul 4, 2014 1:26 PM in response to Loner T

Here's the output:

sudo gdisk /dev/disk1

GPT fdisk (gdisk) version 0.8.10

Partition table scan:

MBR: hybrid

BSD: not present

APM: not present

GPT: present

Found valid GPT with hybrid MBR; using GPT.

Command (? for help): p

Disk /dev/disk1: 976773168 sectors, 465.8 GiB

Logical sector size: 512 bytes

Disk identifier (GUID): CC23DCF4-ADFD-44F0-94BF-15908E15095C

Partition table holds up to 128 entries

First usable sector is 34, last usable sector is 976773134

Partitions will be aligned on 8-sector boundaries

Total free space is 153710781 sectors (73.3 GiB)

Number Start (sector) End (sector) Size Code Name

1 40 409639 200.0 MiB EF00 EFI System Partition

2 409640 469747767 223.8 GiB 0700 Customer

3 469747768 471017303 619.9 MiB AB00 Recovery HD

4 471017472 823062527 167.9 GiB 0700 BOOTCAMP

Command (? for help): i

Partition number (1-4): 2

Partition GUID code: EBD0A0A2-B9E5-4433-87C0-68B6B72699C7 (Microsoft basic data)

Partition unique GUID: A42254FD-CBE8-4FBE-B25E-24F5152205CB

First sector: 409640 (at 200.0 MiB)

Last sector: 469747767 (at 224.0 GiB)

Partition size: 469338128 sectors (223.8 GiB)

Attribute flags: 0000000000000000

Partition name: 'Customer'

Loner T

Level 9

59,513 points

Jul 4, 2014 1:28 PM in response to Iyassou

The partition type needs to be changed via GPT fdisk(disk). The GPT is backed-up via the first command (it will prompt for a filename which will be written to the current local directory). After the backup, the partition type for partition 2 is changed from 0700 (Microsoft...) to HFS/HFS+ (AF00).

sudo gdisk /dev/disk1

<FileName>

AF00

This should allow the currently "broken" Mac to boot.

Here is test I ran (without the write part).

sudo gdisk /dev/disk0

GPT fdisk (gdisk) version 0.8.9

Warning: Devices opened with shared lock will not have their

partition table automatically reloaded!

Partition table scan:

MBR: hybrid

BSD: not present

APM: not present

GPT: present

Found valid GPT with hybrid MBR; using GPT.

Command (? for help): t

Partition number (1-4): 2

Current type is 'Apple HFS/HFS+'

Hex code or GUID (L to show codes, Enter = AF00):

Changed type of partition to 'Apple HFS/HFS+'

Command (? for help): i

Partition number (1-4): 2

Partition GUID code: 48465300-0000-11AA-AA11-00306543ECAC (Apple HFS/HFS+)

Partition unique GUID: 98D8DC3F-F7F8-41A2-B5AA-6FBFC53694BB

First sector: 409640 (at 200.0 MiB)

Last sector: 1452940543 (at 692.8 GiB)

Partition size: 1452530904 sectors (692.6 GiB)

Attribute flags: 0000000000000000

Partition name: 'Customer'

Command (? for help): q

Iyassou Author

Level 1

0 points

Jul 4, 2014 1:39 PM in response to Loner T

Question: when I type w at the end, this message pops up:

Command (? for help): w

Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING

PARTITIONS!!

Do you want to proceed? (Y/N):

Is this a harmless warning and should I say yes or no?

GPT help