[SOLVED] Some UEFI related questions.

scar · 2013-09-30 11:33:11

To the better understanding of this topic, I would first describe my (related) hardware setup:

Gigabyte GA-H77-DS3H motherboard,
one Kingston 16Gb SSD Drive
one Western Digital Sata2 HDD (320 Gb)

First thing is, that I wanted to install Windows 7 (64bits) in UEFI-GPT mode on the Western Digital drive, but simply no UEFI boot option was presented to me when I booted the installation medium. So I left it alone and installed W7 in BIOS-MBR mode.

Then, as the motherboard's BIOS supports UEFI and Legacy Bios booting too, I installed Arch in about ten minutes in UEFI mode on my SSD, with GRUB in UEFI mode. It works.

Now the problem is, that I cannot configure GRUB that it loads Windows from the WD drive.
I've tried several things.

First, I've tried os-prober. It finds absolutely nothing, not even memtest. The windows 7 loader is invisible to this one.

Then I've found this one: https://wiki.archlinux.org/index.php/GR … S-MBR_mode

So I've tried it, made the /etc/grub.d/40_custom with the related data (i.e. partition UUID, hints...), it could not boot.
The problem is, that the ntldr module does not exist (I've checked and double checked /usr/lib/grub/x86_64-efi/ , there is no such module.)

So:

If I want to dualboot in UEFI mode, do I have to install Arch AND Windows in UEFI mode too?
Why does os-prober not find my BIOS-MBR installed Win7?
Why does os-prober not find my Memtest?

(For the moment, I re verted my arch install to boot from a GPT-BIOS partition, and found all my other stuff with os-prober...)

Last edited by scar (2013-10-02 14:03:52)

the.ridikulus.rat · 2013-09-30 14:51:40

You cannot chainload Windows BIOS from UEFI GRUB. Same goes for Windows UEFI from BIOS GRUB. You might have better luck with rEFInd tough. See "Booting Legacy OSes" section in http://www.rodsbooks.com/refind/using.html . Slightly similar issue - https://bbs.archlinux.org/viewtopic.php … 3#p1331373 .

EDIT 1: Since you mention that you have switched the Arch install in your SSD to BIOS-GPT, you can try https://wiki.archlinux.org/index.php/GR … S-MBR_mode to chainload Windows installed in BIOS-MBR mode in HDD. It should work as long as GRUB is installed in BIOS mode (either in the GPT SSD or in the MBR HDD) and the HDD (in which Windows BIOS is installed) stays as MBR. os-prober does not always work properly (more so in case of UEFI) and it is not maintained by GRUB upstream.

EDIT 2: Most likely there should be an option in the BIOS/Firmware setup that disables "Legacy BIOS" (or CSM) support, making sure only UEFI boot mode is enabled. If that exists, you can try enabling "UEFI only" mode, and then try to UEFI boot Windows setup from a FAT32 USB, similar to the way you booted Arch Install ISO in UEFI mode (simply extract the Windows ISO files to the USB and then launch it from the firmware). For more info see https://gitorious.org/tianocore_uefi_du … I_boot_USB and https://gitorious.org/tianocore_uefi_du … I_only_ISO (not related to Linux, but useful for UEFI dual-booters).

EDIT 3: I suggest moving Arch back to UEFI-GPT and re-installing Windows in UEFI-GPT now rather than having to change later in the future when the need arises. If you are adventurous, and want to convert existing Windows BIOS-MBR install to UEFI-GPT, you can try https://gitorious.org/tianocore_uefi_du … OS_to_UEFI .

EDIT 4: Memtest, the one packaged by Arch - https://www.archlinux.org/packages/extr … emtest86+/ , is a BIOS based utility, so it will not work with UEFI GRUB.

Last edited by the.ridikulus.rat (2013-09-30 17:11:26)

srs5694 · 2013-09-30 17:03:41

I agree with the.ridikulus.rat's suggestions. One point, though....

the.ridikulus.rat wrote:

Memtest is a BIOS based utility, so it will not work with UEFI GRUB.

Passmark has a (currently beta) EFI version of memtest86; it's available here:

http://www.memtest86.com/download.htm

Be sure to get the version 5.0 beta.

scar · 2013-09-30 17:30:36

O.K. Thank you for the replies, btw Memtest was not really an urgency, hopefully I don't need it in a close future.
I've tried to disable legacy BIOS, and enable UEFI only, transferred all the files to a USB memstick as the.ridikulus.rat proposed, and it APPEARED in the bootable devices list - only that when I was booting it, I had something like "no bootable media .. blah ... please select proper media... blah...)
What I really do not understand is: why Win refuses to boot the install dvd in UEFI mode. PITA.

[EDIT]

Some days later...

Finally I had the time, so I've picked up another Win7 installer, (to be honest 4 another installers), and the last of them is able to boot in UEFI mode, so it should work now. Thank you, uncle Ballmer. (And LOTS of thanks for all the precedet tries eating up my time.)

So, UEFI linux booting works together only with UEFI Win installs.

Os-prober can be a bit disappointing sometimes, manually adding stuff to /etc/grub.d/40_custom is not.

Memtest is a legacy-BIOS-only utility, I'll give a try to the UEFI-beta-counterpart soon.

Thank you, guys.

Last edited by scar (2013-10-02 14:02:54)

Arch Linux

#1 2013-09-30 11:33:11

[SOLVED] Some UEFI related questions.

#2 2013-09-30 14:51:40

Re: [SOLVED] Some UEFI related questions.

#3 2013-09-30 17:03:41

Re: [SOLVED] Some UEFI related questions.

#4 2013-09-30 17:30:36

Re: [SOLVED] Some UEFI related questions.

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