adamsouthern
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Q: Bootcamp Broken after Resizing and OSX Update

Hello, so after updating to Yosemite 10.10.3, my bootcamp partition, which was previously resized, has become unbootable. I can't read the partition in finder and can't see it in Startup Disk. It, however appears as "disk0s4" in disk utility. I've posted some outputs of commands suggested in another thread. Hopefully this will help fix this issue.

 

Adams-MacBook-Pro:~ Adam$ sudo fdisk /dev/disk0

Password:

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   2 -   25 127  14 [         1 -     409639] <Unknown ID>

2: 03   25 127  15 - 1023 254  63 [    409640 -  255104784] XENIX /usr

*3: 03 1023 254  63 - 1023 254  63 [ 255514424 -    1269536] XENIX /usr

4: 00    0   0   0 -    0   0   0 [         0 -          0] unused    

Adams-MacBook-Pro:~ Adam$ diskutil list

/dev/disk0

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:      GUID_partition_scheme                        *251.0 GB   disk0

   1:                        EFI EFI                     209.7 MB   disk0s1

   2:                  Apple_HFS Macintosh HD            130.6 GB   disk0s2

   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3

   4:       Microsoft Basic Data                         70.0 GB    disk0s4

Adams-MacBook-Pro:~ Adam$ sudo gpt -vv -r show /dev/disk0

gpt show: /dev/disk0: mediasize=251000193024; sectorsize=512; blocks=490234752

gpt show: /dev/disk0: Suspicious MBR at sector 0

gpt show: /dev/disk0: Pri GPT at sector 1

gpt show: /dev/disk0: Sec GPT at sector 490234751

      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  255104784      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC

  255514424    1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

  256783960   96733608       

  353517568  136716288      4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

  490233856        863       

  490234719         32         Sec GPT table

  490234751          1         Sec GPT header

Adams-MacBook-Pro:~ Adam$

Output of the command suggested:

Adams-MacBook-Pro:~ Adam$ sudo dd if=/dev/rdisk0s4 count=1 2>/dev/null | hexdump -C

00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

*

00000200

 

Thanks in advance.

MacBook Pro (Retina, 13-inch, Early 2013), OS X Yosemite (10.10.3), Windows 8.1

Posted on May 7, 2015 9:56 AM

by Loner T,Solvedanswer
Loner T Loner T
Level 7 (24,825 points)
Safari
A:

Leave your Testdisk display and start a new Terminal Window. You need to use the following steps. You will need to install GPT Fdisk (aka Gdisk).

 

If you see any error messages during the following steps, please stop and post back here with the error message. The following steps have values from your Testdisk output (and you can verify) in Steps 7 and 8. Notice the '+' in step 8.

 

Rebuild GPT4 using start/end offsets

 

  1. Sudo gdisk /dev/rdisk0
  2. P  (print the full list of parts)
  3. D  (delete)
  4. 4  (part 4)
  5. N  (new part)
  6. 4  (part 4)
  7. 280403968 - Start offset in bytes  (start point for Bootcamp part)
  8. +209829881  - Size offset (as opposed to End offset)
  9. 0700 (Windows part type)
  10. P  (print list of all parts just to see what changes will be made)
  11. W (Write the new GPT)
  12. Y  (Yes! really write the new GPT)

This will delete and re-write the GPT partition info for /dev/disk0s4.


Rebuild MBR to match the new GPT information thus resetting the Hybrid MBR. Use defaults for other questions (like partition codes). The only values that need modifications are the Boot flags and step 10. Accept all other defaults that Gdisk offers.

  1. Sudo gdisk /dev/disk0
  2. P  (Print list of parts)
  3. R  (Recover)
  4. H (chooses Hybrid)
  5. O (print current Hybrid MBR)
  6. Partitions numbers to be hybridized: 2 3 4
  7. Y  (Good for GRUB question)
  8. N  (part 2 boot flag)
  9. N  (part 3 boot flag)
  10. Y  (part 4 boot flag make NTFS bootable partition)
  11. O  (print current Hybrid MBR)
  12. W (Write the new MBR)
  13. Y (Yes! write the new MBR)
  14. Reboot

 

Here is sample Q&A for this section. Please notice the Press Enter/Return.

 

Place EFI GPT (0xEE) partition first in MBR (good for GRUB)? (Y/N): Y

 

Creating entry for GPT partition #2 (MBR partition #2)

Enter an MBR hex code (default AF): Press Enter/Return

Set the bootable flag? (Y/N): N

 

Creating entry for GPT partition #3 (MBR partition #3)

Enter an MBR hex code (default AB): Press Enter/Return

Set the bootable flag? (Y/N): N

 

Creating entry for GPT partition #4 (MBR partition #4)

Enter an MBR hex code (default 07): Press Enter/Return

Set the bootable flag? (Y/N): Y

 

Test 1 - Does Bootcamp Volume show up in Finder?

Test 2 - Can you see files in Bootcamp Volume?

Test 3 - Can you select Bootcamp in System Preferences -> Startup Disk?

Test 4 - If Test 3 is successful, select Bootcamp and Click Restart.

Posted on May 8, 2015 2:59 PM

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adamsouthern

Q: Bootcamp Broken after Resizing and OSX Update

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