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Bx029297 Author

Level 1

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Issues with hybrid mbr and bootcamp partition

HI, i'm trying to install windows 7 via bootcamp on Mac Os x and created 2 additional partitions.

created the bootcamp partition with bootcamp assistant.

Then while bootcamp was partitioning hit the eject key and to eject the windows installation DVD and quit installation

Went to Disk Utility and created 2 more partitions LINUX SWAP and Ubuntu.

so i understand that the gpt side was created but not the mbr

this is the output of sudo gpt -vv -r show /dev/disk0 :

gpt show: disk0: mediasize=320072933376; sectorsize=512; blocks=625142448

gpt show: disk0: PMBR at sector 0

gpt show: disk0: Pri GPT at sector 1

gpt show: disk0: Sec GPT at sector 625142447

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 136718744 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC

137128384 1269536 3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

138397920 11718744 4 GPT part - 48465300-0000-11AA-AA11-00306543ECAC

150116664 262144

150378808 136221984 5 GPT part - 48465300-0000-11AA-AA11-00306543ECAC

286600792 45156776

331757568 293384192 6 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

625141760 655

625142415 32 Sec GPT table

625142447 1 Sec GPT header

how to i create the hybrid mbr before installing windows 7?

Posted on Jul 6, 2014 5:54 AM

16 replies

Jul 7, 2014 10:22 AM in response to Bx029297

this was definitely not easy to achieve.

It's why I discourage it and recommend VMs or other hardware (dedicated hardware). The current state is working but it's so fragile that even Apple tools including the OS upgrade installer, will break it. Not might. Will. So you may want to write up a cheat sheet on how to recreate the hybrid MBR and spread copies of it everywhere so that you have access to it in the face of an unbootable system. Typically the GPT is not what breaks, but rather the hybrid MBR. However, since Windows booted CSM-BIOS mode ignores both the primary and backup GPTs, it's possible for one or both to become broken. We really only find a way out of this complexity once Apple moves to the minimum UEFI spec supported by Windows and officially supports EFI mode booting for Windows.

Issues with hybrid mbr and bootcamp partition