On Wed, Sep 20, 2023 at 09:02:42AM +0100, Barry wrote:
>
>
>> On 20 Sep 2023, at 01:41, Bill Cunningham <bill.cu1234(a)gmail.com>
>> wrote:
>>
>> I had to reinstall my windows system which is fine it takes
>> care of itself. But, I have to install my entire fedora system from
>> scratch. Is there a way to simply reinstall the boot loader code
>> without having to install from scratch with a UEFI system? I'm sure
>> there is but I don't know about it. There's also a command called
>> "efibootmgr" is this what I am looking for? AFAIK fedora doesn't
>> install more partitions but just code in the /boot/efi partition.
>> How can I reinstall or repair boot loader code without touching the
>> system? Without having to reinstalling from scratch?
>
> In my notes I saved this command for fixing fedora booting on one of
> my systems.
> (I had a system that would fill its EFI variable space and need a
> full reset)
>
> efibootmgr --create --disk /dev/md126 --part 2 --loader
> /EFI/fedora/shim.efi --label Fedora
>
> In this case /dev/md126 is my raided fedora disk, replace with your
> disk.
>
> /dev/md126p2 - VFAT - EFI
>
> Partition 2 is what is mounted on /boot/EFI, change the 2 as needed.
>
From my notes :) .. :
-----
add a boot entry:
efibootmgr -c -d /dev/sdb -p 1 -w -L Debian -l "\EFI\debian\grubx64.efi"
-----
If I recall correctly:
This command above was done a machine where /dev/sdb was a disk where
Debian was already installed. The 'man' page should explain the rest
of the options.
see:
https://wiki.debian.org/UEFI#efibootmgr_example_3_-_add_a_new_boot_entry
At the end of "man efibootmgr" you should find an example for a Fedora
install - it says "The default OS Loader is \EFI\fedora\grub.efi"
But that looks wrong to me. My guess would be that this should say for
a nowadays Fedora install probably:
"\EFI\fedora\shim.efi"
The latter at least was what I saw with a quick Internet search and
the output from entering "efibootmgr" on my own Fedora install here.
Excerpt:
[ ....]
Boot0002* Fedora HD(1,GPT,[..])/File(\EFI\fedora\shim.efi)
[ .... ]
See the "\EFI\fedora\shim.efi" section above..
I'd simply take some Live system on a thumb, boot it, and then have a
look at the output of
# efibootmgr
and proceed with that info ...
Good luck!
Wolfgang
Would it be that entering the simple grub2-install (like with a mbr
boot) would work? That's the important thing, to rescue a fedora
system and get it running. The other things about uefi I could learn
in time.