Iyassou
Level 1 (0 points)

Q: GPT help

https://discussions.apple.com/message/26125763#26125763

 

Output of sudo fdisk /dev/rdisk0 :

 

Disk: /dev/rdisk0geometry: 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

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Iyassou

Q: GPT help

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  • by Iyassou,

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

  • by Loner T,

    Loner T Loner T Jul 4, 2014 1:50 PM in response to Iyassou
    Level 7 (24,825 points)
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    Jul 4, 2014 1:50 PM in response to Iyassou

    The answer here should be yes. This can be changed since you have the ability to access the disk in target disk mode. There is also a backup of the GPT that can be reloaded, if necessary. I assume you have the backup file on the working MAC and not on the original non-working MAC. If not, I would copy it after you do a write.

     

    Please try booting to MAC OS X on the "broken" MAC after you write and power cycle it. Using the ALT key should tell you quickly if the changes are sufficient or not. Running an additional bless may not be required.

  • by Iyassou,

    Iyassou Iyassou Jul 4, 2014 1:56 PM in response to Loner T
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    Jul 4, 2014 1:56 PM in response to Loner T

    THANK YOU!! I CAN NOW BOOT INTO MAC!! Although, I have to ask, is there any way to save my BOOTCAMP partition?

  • by Loner T,

    Loner T Loner T Jul 4, 2014 2:01 PM in response to Iyassou
    Level 7 (24,825 points)
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    Jul 4, 2014 2:01 PM in response to Iyassou

    Yes, we need to address the Bootcamp part now. If you used the ALT key, did a bootable Windows also show up? Do you see Bootcamp in Finder and a Bootcamp volume?

  • by Iyassou,

    Iyassou Iyassou Jul 5, 2014 11:14 AM in response to Loner T
    Level 1 (0 points)
    Jul 5, 2014 11:14 AM in response to Loner T

    When I startup my mac pressing ALT I can see a "Windows" volume, but when I boot into it, I get the error message "Missing Operating System".

    In Finder, there is no BootCamp volume.

    ALTHOUGH, in Disk Utility I can see my BootCamp volume under the name "disk0s4" . It's about 180GB, which was the same space I allocated to my BootCamp partition; so yeah, my BootCamp partition is there, but I can't access it.

  • by Loner T,

    Loner T Loner T Jul 5, 2014 11:33 AM in response to Iyassou
    Level 7 (24,825 points)
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    Jul 5, 2014 11:33 AM in response to Iyassou

    If you have the Windows Installation media, you can do startup repair as noted here...

     

    http://windows.microsoft.com/en-us/windows7/products/features/startup-repair

     

    Depending on how badly the Windows side is corrupted, you may be able to re-install, without losing your data. I assume you have Windows 7. Windows XP has a recovery console as well.

  • by Iyassou,

    Iyassou Iyassou Jul 6, 2014 1:02 AM in response to Loner T
    Level 1 (0 points)
    Jul 6, 2014 1:02 AM in response to Loner T

    The start-up repair did not work . But I have a question, the format of my Windows partition is now FAT (MS-DOS), its original format was NTFS. Could this be the problem preventing it from not booting?

  • by Loner T,

    Loner T Loner T Jul 6, 2014 5:36 AM in response to Iyassou
    Level 7 (24,825 points)
    Safari
    Jul 6, 2014 5:36 AM in response to Iyassou

    It is one likely problem. Disk Utility manipulations of Bootcamp partitions are fraught with issues. It will not boot if it is FAT. You can use testdisk (http://www.cgsecurity.org/wiki/TestDisk) to verify if this is the correct partition or not.

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