[edk2] can ovmf boot from mbr partioned disk

[Fanhenglong]

Hi all,

I have some mbr partioned disk, my system only support to boot by uefi,
I can't convert mbr to gpt,
So I want to know if I can use ovmf to boot mbr disk.


Thanks!

[Andrew Fish]

Post by Fanhenglong
Hi all,
I have some mbr partioned disk, my system only support to boot by uefi,
I can’t convert mbr to gpt,
So I want to know if I can use ovmf to boot mbr disk.

UEFI supports booting from MBR, and GPT.

Thanks,

Andrew Fish

Post by Fanhenglong
Thanks!
------------------------------------------------------------------------------
_______________________________________________
edk2-devel mailing list
https://lists.sourceforge.net/lists/listinfo/edk2-devel <https://lists.sourceforge.net/lists/listinfo/edk2-devel>

[Fanhenglong]

发件人: Andrew Fish [mailto:***@apple.com]
发送时闎: 2015幎8月16日 11:44
收件人: Fanhenglong
抄送: edk2-***@lists.sourceforge.net
䞻题: Re: [edk2] can ovmf boot from mbr partioned disk


On Aug 15, 2015, at 7:24 PM, Fanhenglong <***@huawei.com<mailto:***@huawei.com>> wrote:

Hi all,

I have some mbr partioned disk, my system only support to boot by uefi,
I can’t convert mbr to gpt,
So I want to know if I can use ovmf to boot mbr disk.

Post by Andrew Fish
UEFI supports booting from MBR, and GPT.

In uefi boot mode I can’t install windows or linux guest os on mbr partition,
Maybe uefi only supports booting from mbr and can’t install on mbr?

If for sure, I have to create uefi boot file in mbr partitioned disk.


Thanks
Henglong Fan

[Andrew Fish]

Post by Fanhenglong
发送时闎: 2015幎8月16日 11:44
收件人: Fanhenglong
䞻题: Re: [edk2] can ovmf boot from mbr partioned disk
Hi all,
I have some mbr partioned disk, my system only support to boot by uefi,
I can’t convert mbr to gpt,
So I want to know if I can use ovmf to boot mbr disk.

Post by Andrew Fish
UEFI supports booting from MBR, and GPT.

In uefi boot mode I can’t install windows or linux guest os on mbr partition,
Maybe uefi only supports booting from mbr and can’t install on mbr?

Why not? UEFI does not Legacy Boot from the MBR boot sector. It reads a file from a FAT file system. So you can dual boot all you want.

Thanks,

Andrew Fish

Post by Fanhenglong
If for sure, I have to create uefi boot file in mbr partitioned disk.
Thanks
Henglong Fan

[Rod Smith]

In uefi boot mode I can’t install windows or linux guest os on mbr
partition,
Maybe uefi only supports booting from mbr and can’t install on mbr?

Windows and most Linux distributions have their own prohibitions against
installing to MBR disks. Your description is a little unclear, but
you're probably running into this issue.

I can’t convert mbr to gpt,

Why not? The OS installer should permit you to do this, although in some
cases you'll need to jump through some hoops to do it. (Note that this
may destroy other OSes already installed to the disk, or at least render
them unbootable until an EFI-mode boot loader is installed.)

[Andrew Fish]

Post by Rod Smith

In uefi boot mode I can’t install windows or linux guest os on mbr
partition,
Maybe uefi only supports booting from mbr and can’t install on mbr?

Windows and most Linux distributions have their own prohibitions against
installing to MBR disks. Your description is a little unclear, but
you're probably running into this issue.

I can’t convert mbr to gpt,

Why not? The OS installer should permit you to do this, although in some
cases you'll need to jump through some hoops to do it. (Note that this
may destroy other OSes already installed to the disk, or at least render
them unbootable until an EFI-mode boot loader is installed.)

Not to mention it is OVMF, so you could have an MBR disk and a GPT disk.

For legacy BIOS boot you need C: and magic sectors on an MBR formatted disk (sector zero, and cheat sectors lots of folks try to use).
For EFI you boot from a named file on a FAT32 system partition. The system partition can contain an unlimited number of OS loaders. The OS installer writes an NVRAM variable that sets the name of the 1st stage OS loader (EFI Application).

Thanks,

Andrew Fish

Post by Rod Smith
--
Rod Smith
http://www.rodsbooks.com
------------------------------------------------------------------------------
_______________________________________________
edk2-devel mailing list
https://lists.sourceforge.net/lists/listinfo/edk2-devel

------------------------------------------------------------------------------

[Fanhenglong]

-----邮件原件-----
发件人: Andrew Fish [mailto:***@apple.com]
发送时间: 2015年8月17日 2:27
收件人: Rod Smith
抄送: edk2-***@lists.sourceforge.net
主题: Re: [edk2] 答复: can ovmf boot from mbr partioned disk

Post by Rod Smith

In uefi boot mode I can’t install windows or linux guest os on mbr
partition,
Maybe uefi only supports booting from mbr and can’t install on mbr?

Windows and most Linux distributions have their own prohibitions
against installing to MBR disks. Your description is a little unclear,
but you're probably running into this issue.

I can’t convert mbr to gpt,
Why not? The OS installer should permit you to do this, although in
some cases you'll need to jump through some hoops to do it. (Note that
this may destroy other OSes already installed to the disk, or at least
render them unbootable until an EFI-mode boot loader is installed.)

Not to mention it is OVMF, so you could have an MBR disk and a GPT disk.
For legacy BIOS boot you need C: and magic sectors on an MBR formatted disk (sector zero, and cheat sectors lots of folks try to use).
For EFI you boot from a named file on a FAT32 system partition. The system partition can contain an unlimited number of OS loaders. The OS installer writes an NVRAM variable
that sets the name of the 1st stage OS loader (EFI Application).

I will try this way

Thanks
Henglong Fan


------------------------------------------------------------------------------

[Fanhenglong]

-----邮件原件-----
发件人: Rod Smith [mailto:***@rodsbooks.com]
发送时间: 2015年8月17日 1:55
收件人: edk2-***@lists.sourceforge.net
主题: Re: [edk2] 答复: can ovmf boot from mbr partioned disk

In uefi boot mode I can’t install windows or linux guest os on mbr
partition,
Maybe uefi only supports booting from mbr and can’t install on mbr?

->Windows and most Linux distributions have their own prohibitions against installing to MBR disks. Your description is a little unclear, but you're probably running into this issue.yh
Yh, I wanted to install efi boot loader in mbr partion, and test to boot mbr by ovmf in xen4.5.
I failed to install guest os Suse11 sp3,or windows 2008 r2 64, on mbr partition, beause the partition is seted gpt after os os install completely.

Now I did't find another way to install efi-mod boot loader in mbr partion instead of install guest os directly.

->Earlier, you wrote:
->> I can’t convert mbr to gpt,

->Why not? The OS installer should permit you to do this, although in some cases you'll need to jump through some hoops to do it. (Note that this may destroy other OSes already installed to ->the disk, or at least render them unbootable until an EFI-mode boot loader is installed.)
--
Rod Smith
***@rodsbooks.com
http://www.rodsbooks.com

------------------------------------------------------------------------------
_______________________________________________
edk2-devel mailing list
edk2-***@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/edk2-devel
------------------------------------------------------------------------------