[olug] anyone know how to fix the bootloader on EFI systems?

[Rob Townley]

Some thoughts:

Sounds much like my experience when changing a BIOS storage option between
IDE | RAID | AHCI.

Maybe there are some bugs in the firmware.  I would be checking for a new
BIOS / EFI version for your system.

Do not make SuperGrub2 as it is most likely already on SysRescCD or similar
rescue CDs.

 SysRescCD supports EFI.

I kinda recall that more problems with 32bit vs 64bit.  Are you sure there
is a match between the boot media bitness and what is on the HDD.





On Mar 10, 2017 9:42 PM, "Kevin D. Snodgrass" <kdsnodgrass at yahoo.com> wrote:

> I don't have any EFI systems, so no "actual knowledge" here, but....
> onwards :)
> Make a bootable thumbdrive, Fedora install images are exactly that, boot
> to it, if grub-efi exists on the image (which it probably does), run that
> from command line to do the voodoo for efi install. If grub-efi does not
> then use DNF to install it to the thumbdrive, and then run it.
> Seems logical at least. (shrug) Kevin D. Snodgrass
>
>       From: Lou Duchez <lou at paprikash.com>
>  To: Omaha Linux User Group <olug at olug.org>
>  Sent: Thursday, March 9, 2017 10:32 AM
>  Subject: Re: [olug] anyone know how to fix the bootloader on EFI systems?
>
> No luck yet, and for the sake of my blood pressure I'm setting the
> matter aside for now.
>
> Some things I have tried and the roadblocks I have encountered:
>
> 1)    Various instructions say to run grub2-install ... I think this is
> the root of the problem, you SHOULDN'T run grub2-install on an EFI
> system.  Apparently, on EFI the MBR doesn't change from kernel version
> to kernel version (or distro version to distro version), it's allegedly
> smart enough to find the appropriate bootloader.  That's where I screwed
> things up I think, I changed the MBR.
>
> 2)    The fix is supposed to be reinstalling the package grub2-efi,
> which will fix the MBR.  But that would require booting to normal Linux;
> I did once or twice but I can't now.  If I can somehow get the thing to
> boot normally just once more I can sort this out.
>
> 3)    grub rescue options, like setting "prefix" and "root" ... haven't
> found options that work.
>
> 4)    I've tried making Super Grub2 bootable drives but I can't manage
> to make one that actually boots.  I'm using a Windows 7 machine to try
> to build them, shut up I have my reasons.  :-)
>
> Using the Fedora installation media I can at least get at the file
> system, mount drives, and so forth.  All the user data has been copied
> off and that makes the thought of a full reinstallation more palatable,
> but I still feel like there should be some way to fix this mess.
>
> I also feel like EFI shouldn't make this such a fearsome process. It
> ought to be something that can be fixed simply, and I feel like I'm
> almost there, it's just that one step.
>
>
> > Did you find a solution to this? I fear EFI thanks to these things.  It
> seems like the fix would be to boot a live distro and (re)install a boot
> loader that works with EFI? grub should work with the right options, I
> believe.
> >
> > Possibly relevant: https://wiki.archlinux.org/
> index.php/GRUB#UEFI_systems
> >
> > -- Kava
> >
> >
> >
> > -----Original Message-----
> > From: olug-bounces at olug.org [mailto:olug-bounces at olug.org] On Behalf Of
> Lou Duchez
> > Sent: Thursday, 9 March, 2017 00:35
> > To: Omaha Linux User Group <olug at olug.org>
> > Subject: [olug] anyone know how to fix the bootloader on EFI systems?
> >
> > Well I screwed up.  I ran grub2-install on an EFI system, and apparently
> one shouldn't do that.  Now my system won't boot without the help of the
> Fedora installation media, and even then I can only get it to the grub
> command line, or (with the right set of gyrations and some good fortune)
> single-user mode and access to the entire LVM file system.
> >
> > Any suggestions on how to fix the MBR (which is, I believe, where the
> problem lies)?
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