[olug] Fedora 26 upgrade notes

[Lou Duchez]

As is my habit, here is my report on upgrading Fedora 25 to 26 over SSH 
on a variety of computers.  Last time 'round I screwed up big time on a 
new laptop that was booting via EFI rather than BIOS, so I managed to 
clobber the Fedora boot entry.  One of the kind souls here pointed me to 
the rEFInd utility at http://www.rodsbooks.com/refind/, and with its aid 
I was able to get the system running again.  And with the instructions 
I'm listing below (and the Fedora utility "efibootmgr") I was even able 
to restore the boot process to its normal, unbroken condition on that 
laptop.

These same instructions will generally work for going from any version 
of Fedora to its successor; I used very much the same to get from 24 to 
25, 23 to 24, etc.

1)    Prepare for the upgrade with the following (where in this case 
"[NEWVERSIONNUMBER]" should be changed to "26"):

dnf update
rpm --import 
/etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-[NEWVERSIONNUMBER]-$(uname -i)
dnf install screen
dnf clean all
reboot

2)    Go to the command prompt, su to root, and then run "screen" to get 
into a terminal window that, should the SSH connection break, will 
continue running and even let me connect to it again.

3)    Within my window, run the following (where in this case 
"[NEWVERSIONNUMBER]" should be changed to "26"):

dnf --releasever=[NEWVERSIONNUMBER] --setopt=deltarpm=false 
--allowerasing distro-sync

4)    Fixing the boot process!  This is what I got wrong last time 
around.  First determine whether you're booting with EFI or with BIOS by 
running:

         dmesg | grep "EFI v"

         If it comes back blank, you have BIOS.  If it comes back with 
something like "[    0.000000] efi: EFI v32.31 by American Megatrends", 
it's EFI.

5)    FOR BIOS BOOTING ONLY:

         /usr/sbin/grub2-install [BOOTDEVICE]

         You can determine [BOOTDEVICE] by running:

         df | grep "\/boot$"

         And if it comes back with, say, "/dev/sdc1", the boot device is 
"/dev/sdc".

6)    FOR EFI BOOTING ONLY:

         dnf install grub2-efi grub2-efi-modules shim
         dnf reinstall grub2-efi grub2-efi-modules shim

         Then look for "/boot/efi/EFI/fedora/grub.cfg".  If it exists 
(it very probably does), you should be good.  If it doesn't, you will 
need to build a copy.  Try running "grub2-mkconfig -o 
/boot/efi/EFI/fedora/grub.cfg"; if that works, great.

7)    Reboot.