Re: [Bug 1024383] Re: update-grub generates only BIOS based menu entries for Windows, even on UEFI systems
On 5/18/2013 12:14 AM, Jordan wrote: > Upstream grub has done a lot of work to make sure that you *can* have > support for multiple platforms installed and in use at the same time, > with the same config. I've notice that same thing. Right after I suggested "chainloader-efi" and "chainloader-mbr" entries, I came across references to *already* supported options for grub's "search" command, like "--hint-efi", "--hint-bios", and "--hint-baremetal"... all of which can supersede the "--hint" option. So, it appears that upstream is already thinking along the lines of "one grub to rule them all". -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1024383 Title: update-grub generates only BIOS based menu entries for Windows, even on UEFI systems To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1024383/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 1024383] Re: update-grub generates only BIOS based menu entries for Windows, even on UEFI systems
On 5/17/2013 8:17 AM, Phillip Susi wrote: > You don't seem to have understood the passage you quoted. Let me try > rephrasing it: when you boot from the livecd and update grub, you > first chroot into the hard drive, so you are running the update-grub > version on the hd, not the cd. True, looking back through it, I think I misinterpreted it. I took the original idea to be "use the mode (UEFI vs BIOS) which was used for this current boot session". You can generate a grub.cfg for another system without needing to chroot. grub-mkconfig lets you redirect the output to any file you want. So, what's to prevent a user from booting a recovery CD and, without using chroot, using: grub-mkconfig -o /media/MyRealUbuntuPartition/boot/grub/grub.cfg > We're not going to support having both installed at the same time and > using the same config. You need to pick which mode you want to use > and stick with it, not flip flop every other boot. In addition, > Windows can not be booted in bios mode on a GPT disk, so you have to > use grub-efi anyhow. But other OS's *can*. I can boot my linux partitions in UEFI or BIOS mode. Furthermore, linux is what I turn to when I have trouble booting any of my partitions. If I can just get to a linux prompt, with fdisk/parted/grub/etc, then I can usually fix any other booting problems. So, it would be helpful to be able to boot a linux partition from BIOS mode if the EFI SP gets hosed. You can choose not to support that; that's your choice, but I think there are scenarios wherein it would be useful. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1024383 Title: update-grub generates only BIOS based menu entries for Windows, even on UEFI systems To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1024383/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1024383] Re: update-grub generates only BIOS based menu entries for Windows, even on UEFI systems
Phillip Susi wrote:
> On 01/08/2013 09:41 PM, YannUbuntu wrote:
> > No, don't rely on the mode where grub-update is used !
> > Counter-examples: 1) Windows is installed in UEFI mode but
> > update-grub is used from a Ubuntu32bit liveCD (which cannot be
> > booted in UEFI mode, see Bug #102 ).
> > ...
> You don't run update-grub from a live session; you have to chroot into
> the install and run it from there, where you are running the correct
> version, regardless of how you booted the livecd.
> ...
No, I think Yann is absolutely correct about this. My laptop can boot in
UEFI, BIOS, or a "mixed" mode (where it looks for a UEFI partition and
then, if not found, looks for a MBR boot record). The point, however, is
that I can boot SuperGRUB or a live-CD via BIOS/MBR booting off of a CD
or USB drive, and then mount the linux partition on my hard-drive, and
then run update-grub from there. That would be a case where my computer
booted via BIOS/MBR *just* for that recovery session, when "normal"
booting is going to be done via UEFI.
I've only been wrestling with GPT/UEFI for a couple of days, but I think
I'm starting to get an idea of the solution which is needed. For myself,
at least, the *ideal* solution would be to have the option of installing
GRUB to the EFI System Partition *and* to the MBR boot-record, so that
GRUB could be reachable no matter what boot mode I put my computer into
(and perhaps this is already possible, by installing both grub-efi and
grub-pc on the system. I haven't tried).
But it seems that the more-critical part of the solution would be for
there to be grub.conf directives specific to MBR and UEFI booting.
Imagine, for example:
menuentry "Windows 8" {
set root-efi=(hd0,gpt2)
set root-mbr=(hd0,2)
chainloader-efi/EFI/microsoft/BOOT/bootmgfw.efi
chainloader-mbr +1
}
The need for separate "root=" entries could probably be avoided, but you
get the idea. There could still be support for plain "chainloader"
directive, but that value would be superseded by the more-specific
directives. Then, the grub-pc binary would look for additional
"chainloader-mbr" directives and the grub-efi binary would look for
additional "chainloader-efi" directives.
But that's going to take time and planning on the part of the up-stream
grub2 devs. In the short-term, however, I think update-grub should
probably be modified to use the EFI-compatible version of the
chainloader argument if it detects a mounted EFI partition (or whatever
test it uses to determine whether to use "set root=(hd0,1)" or "set
root=(hd0,gpt1)".
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Title:
update-grub generates only BIOS based menu entries for Windows, even
on UEFI systems
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