Chainloading Windows 7 EFI, two HDDs.

Grabbe · 2014-04-07 12:01:11

My setup is two hard drives, the first one is Windows 7 (this is actually an SSD, but it shouldn't matter right?) and seconds is Arch (new installation). Both of the HDDs have a EFI-partition, and my MB is set to boot from the second HDD (Grub2).
I have no idea how to chainload the EFI-partition that my Windows 7 uses from Grub2. The Windows drive is MSDOS-partitioned and Linux is GPT.

I've tried looking at guides, but they all call for chainloading /efi/Microsof/bootmgfw.efi - which does not exist in either of the EFI-partitions. Hence https://wiki.archlinux.org/index.php/Gr … _systems_2 didn't really work.
There is one this that is kind of wierd, and that is the bootmgr-file on my first EFI-partition (I believe they are called ESP?). Does this indicate that it's not actually booting from EFI or what is the deal?

The error messages are mostly that it didn't boot an EFI-partition. Linux boots no problem.

Mr.Elendig · 2014-04-07 13:13:58

Just use one $esp, mount it to /boot in arch and install gummiboot unless you need the fancy features in grub

the_shiver · 2014-04-07 14:10:17

Grabbe wrote:

The Windows drive is MSDOS-partitioned and Linux is GPT.

that might also be an issue because microsoft "because reasons" only allows uefi+gpt OR bios+mbr booting

Grabbe · 2014-04-07 15:41:42

the_shiver wrote:

Grabbe wrote:
The Windows drive is MSDOS-partitioned and Linux is GPT.
that might also be an issue because microsoft "because reasons" only allows uefi+gpt OR bios+mbr booting

I don't really have any problems booting W7 standalone... So it SHOULD work, the question is how to fix it.

the.ridikulus.rat · 2014-04-07 23:37:47

Grabbe wrote:

the_shiver wrote:
Grabbe wrote:
The Windows drive is MSDOS-partitioned and Linux is GPT.
that might also be an issue because microsoft "because reasons" only allows uefi+gpt OR bios+mbr booting
I don't really have any problems booting W7 standalone... So it SHOULD work, the question is how to fix it.

Windows is installed in BIOS-MBR mode in the other HDD. UEFI grub(2) does not support chainloading bios boot code, irrespective of whether BIOS compatibility mode exists in the UEFI firmware or not. Thats what "the_shiver" actually meant to say. When you are booting win7 standalone, the firmware boots via its bios compatibility mode.

So you might need to either migrate win7 to uefi-gpt which is possible https://gitorious.org/tianocore_uefi_du … OS_to_UEFI but needs to be done manually and not officially supported by microsoft (no issues should occur with windows activation with same product key since it is technically tied to the hardware, not the boot mode), or you have to change linux to bios-gpt or bios-mbr config so that you can use one bios bootloader to boot both windows and linux.

Since you have already partitioned the linux HDD as gpt, I suggest installing BIOS grub(2) in the GPT HDD, and chainload win7 in the 2nd HDD from the BIOS-GPT grub(2) which should work, and is much easier than changing windows to uefi-gpt.

EDIT: Added related info to https://wiki.archlinux.org/index.php/Wi … FI_vs_BIOS

Last edited by the.ridikulus.rat (2014-04-13 20:13:02)

the.ridikulus.rat · 2014-04-13 20:40:46

@Grabbe: You can also try rEFInd http://rodsbooks.com/refind/using.html#legacy .

Arch Linux

#1 2014-04-07 12:01:11

Chainloading Windows 7 EFI, two HDDs.

#2 2014-04-07 13:13:58

Re: Chainloading Windows 7 EFI, two HDDs.

#3 2014-04-07 14:10:17

Re: Chainloading Windows 7 EFI, two HDDs.

#4 2014-04-07 15:41:42

Re: Chainloading Windows 7 EFI, two HDDs.

#5 2014-04-07 23:37:47

Re: Chainloading Windows 7 EFI, two HDDs.

#6 2014-04-13 20:40:46

Re: Chainloading Windows 7 EFI, two HDDs.

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