Issues with hybrid mbr and bootcamp partition

Please see Christopher's response in the original thread.

In the MBR, your first partition will be from 1 through 331757567. The second partition starts at 331757568 .

- gdisk

- recovery menu, with r command

- create new hybrid mbr, with h command

a. Only specify the number for the Windows GPT partition when asked what to add, so in your case this is 6.

b. Answer yes to placing the GPT first in the MBR.

c. Accept the default MBR hex code (just hit return).

d. Set the boot flag.

Thing is, you really need to install Linux first because the partitioning tool (parted) most often used with Linux distros, is going to alter the GPT because the type codes for partitions 4 and 5 aren't correct right now. So when those get changed, it's going to write out a new GPT, and that will obliterate the hybrid MBR. So I'd install Linux first. Then make the hybrid MBR. Then install Windows.

shouldn't it be 8300 for LINUX Filesystem (UBUNTU) and 8200 for LINUX SWAP or it just doesn't matter?

If you've already installed Linux, then we've found a bug, because the partition type GUIDs for the two Linux partitions weren't set correctly. Linux ignores type codes, so it's of no consequence to Linux, but any partition type code of AF00 invites OS X to inspect the partition contents, which it won't recognize, and it'll persistently suggest you initialize the partition. So yes the partition type codes should be 8200 and 8300 respectively. I would do this before creating the hybrid MBR, even though in this case the sequence probably doesn't matter.

The Linux installation should update the Swap and Ubuntu partitions correctly. As Christopher says

So I'd install Linux first. Then make the hybrid MBR. Then install Windows.

(Delayed updates from the discussions. 😟 )

No you don't need to start over. Unlike other tools gdisk shows the whole truth about both partition maps. Short of a bug it's completely reliable. What you have is exactly what you need. So assuming Ubuntu is already installed, your next step is Windows installation. What ought to happen is you'll get something like this in the Windows installer. It will show the MBR #1 partition (which is the GPT, EFI System partition, OS X and Linux partitions combined) as having no free space. It will have selected the 2nd partition which is entirely free. You can just click the next button and it'll format it NTFS and start installation.

Oh a small word of warning though. I'm assuming GPT partition 6 for Windows hasn't been formatted.

OS X Boot Camp Assistant likes to format the Boot Camp volume it creates as FAT32. So that needs to be reformatted NTFS in the Windows installer by clicking on Drive options (advanced), selecting the correct partition, and clicking the Format button. Then clicking Next. I haven't tested this recently but it's vaguely possible that the installer will happily install to FAT32 without reformatting it, if it's already FAT32 and you just click Next, and you don't want that. You definitely want to install on NTFS so if you're uncertain, go to Drive options (advanced) and format partition 2.

The W7 installer refuses FAT and requires NTFS, but XP will happily install, based on my last test.

Bx029297 wrote:

LONER T, is there a way to convert it beforehand to NTFS?

My recommendation is to let the Windows Installer convert it.

I will let Christopher comment on this, but the sequence should be

1. Install OS X.

2. Install Linux.

3. Ensure the GPT is appropriate with type codes/partition type GUIDs.

4. Create a Hybrid MBR with GPT #6 as MBR #2. This should be FAT.

5. Install Windows and choose MBR #2 partition which will be converted from FAT to NTFS. MBR#2 and GPT#6 should be type 07/partition type GUID EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

So my question is can i go ahead and install first linux then windows (which is already formatted as MS DOS (FAT 32) provided that i have already created the hybrid MBR as you can see above.

1. I would change the type code for partition 4 to 8200, and partition 5 to 0700 before installing Linux. Use 0700 because due to poor planning, the parted developers borrowed the Microsoft basic data partition type GUID for Linux partitions on GPT disks. Only very recent installers understand type code 8300.

2. Install Linux, this will remove the hybrid MBR you've already created.

3. In gdisk recreate the hybrid MBR.

4. Install Windows.

need it is crucial that i do not use bootcamp to create a bootcamp partition but gdisk instead to create every partitions,

Assuming you already have Windows install media prepared and it boots the Windows installer, you don't need Boot Camp Assistant for anything.

LONER T, is there a way to convert it beforehand to NTFS?

No, just reformat it NTFS in the Windows installer.

Yes, although swapping steps 2 and 3 if Disk Utility was used to create all of the partitions in advance.

The other way to do it is only resize OS X and create one pile of free space for Linux and Windows; let the Linux installer do its own partitioning from free space while leaving some free space for the future Windows installation. Then in Linux or OS X's gdisk, you'd a.) Fix up any partition type codes as needed; b.) create a new partition for Windows with all remaining free space; then c.) create the hybrid MBR; then d.) Install Windows which ought to see only partition 2 (i.e. MBR partition 2, a.k.a. GPT partition 6 in this case) as a target partition for installation.

Obviously part of the confusion is that there are multiple ways to do things...

Good to see it work. 😎