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

[Kevin D. Snodgrass]

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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