Windows/Linux GPT/MBR hybrid

duke11235 · 2009-10-31 18:26:05

Is there an issue with installing grub or grub2 to the mbr in a gpt/mbr hybrid? I've discovered that apple's boot code is very thin on booting from usb and I can't make it boot.

So can I install Windows, then install Arch with grub on the mbr, and still be able to boot them? If this was then possible to boot with Refit or Apple's firmware it would solve my linux problem. Thank You

sweetandy · 2009-11-01 01:26:10

I'm currently on a Mac OS X / Arch dual-boot system (in Arch of course). It took me a number of reinstalls of OS X to get it right, but I eventually did. Note: DO NOT install grub to the MBR. (Read below for details.) Here's some issues I ran into:

I *am* using rEFIt. For me, in order to install Arch, I could not use a Guid partition table straight, I had to have rEFIt make it a hybrid GPT/MBR from the rEFIt boot screen.

Here's the problem with that: GPT can have quite a few primary partitions... in fact, that's all you can have. No extended partitions allowed. This became a problem when it came to the 1) required Apple boot partition, 2) the Apple HFS+ partition, 3) /boot 4) SWAP 5) / (root). Reason? When you, from the rEFIt menu, make it a GPT/MBR hybrid, you max out at 4 partitions and cannot make extended ones to support more. I lost my / partition several times before I realized I couldn't use a separate /boot partition.

Also, install Grub to your / (root) partition (since you probably won't be able to have a /boot partition; otherwise put it there). That way, you select the sexy penguin from the rEFIt menu at startup, and then get the GRUB menu. Don't forget adding vga=773 to your boot line, or whatever resolution you use. Framebuffers are very nice on Macs.

Any more specific questions, ask. I'll be checking this thread regularly.

PS. I don't know about having Windows too... I'd run out of partitions. I guess you could have a swap file instead of a partition, but it'll prolly slow you down.

PPS. I used Parted Magic for my repartitioning, since it was prior to converting it to to a GPT/MBR hybrid, and cfdisk (on the Arch install CD) doesn't support the editing of GUID PTs.

PPPS. Screw it, I was gonna wait for you to post again but here's my umpteenth edit: a terse walkthrough of how I did my install:
http://sweetandy.blogspot.com/2009/10/d … linux.html

Last edited by sweetandy (2009-11-01 02:19:40)

duke11235 · 2009-11-01 04:36:03

What I think I'll do is install boot, root var,home, and swap on one physical lvm volume. Then I'll encrypt the home, swap, root and var partitions, and leave boot unencrypted. That'll be in one partition. The thing I need to test is
A: Can refit understand lvm, and if so can i boot grub2 from a lvm partition
B: If not, I'll create a grub image and boot from cd.
C. I would install grub2 to a usb drive, but Refit has issues booting usb
D: If this is somehow possible, I'll beable to install WIndows next

Instructions on making a bootable grub disk are here:
http://www.justlinux.com/forum/showthre … did=152790

PS. You don't need partition magic, you can use parted, which is included in the install disc

Last edited by duke11235 (2009-11-01 05:55:49)

Arch Linux

#1 2009-10-31 18:26:05

Windows/Linux GPT/MBR hybrid

#2 2009-11-01 01:26:10

Re: Windows/Linux GPT/MBR hybrid

#3 2009-11-01 04:36:03

Re: Windows/Linux GPT/MBR hybrid

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