I just had a nightmare with the latest update in Fedora 28, there is some kind of regression in this new package:
https://bodhi.fedoraproject.org/updat...
To fix it i had to do this: (quoted from this reddit post https://www.reddit.com/r/Fedora/comme...helplatestsmallupdateandtotal_blank/
Basically there has been a fuck up with this up date:
https://bodhi.fedoraproject.org/updat...
It seems some computers (well, mine at least) won't boot any more if they are in the UEFI boot mode (which most will be).
Your mission, should you choose to accept it, is to undo this evil update, and then hunt down the person who approved it and administer a harsh punishment :) Not really. You need to try and boot using the old CSM mode and see if you can get into your computer.
Every BIOS is different, but you should have a 'boot menu', it may be available by pressing F8 on boot, or maybe you need to go into the BIOS and select it. There you can choose what device to boot from. If the Gods are smiling on you there will be 2 entries for your main hard drive, one has UEFI in front of it, the other doesn't. Select the one that DOES NOT and see if it boots. If it does, congratulations, you have defeated the level one boss! If not, afraid you will need to see the other responses in this thread to see the 'hard core' way of doing it. I have not done that, so can't help.
If you can get into the system then go to the bodhi link above, select tab, and you will see a list of files with links. These are the portal to success! Click the first link takes you here:
https://koji.fedoraproject.org/koji/b...
This is the latest BAD version you don't want, you want the last version that worked, so click on 'Package Name' efibootmgr and go here:
Only the files that end fc28 are any good to you, so go to the next newest version:
https://koji.fedoraproject.org/koji/b...
and you want the x86_64 version! This is the tedious manual process you must perform for all the files because the Fedora sudo dnf history undo last command does not seem to hang on to the last version in the cache! Not sure the point of this command if it does jack shit, but it helped me locate the files I needed.
You need to follow the above method to get these files, with the EXACT same names:
shim-x64-13-4.x86_64.rpm
shim-ia32-13-4.x86_64.rpm
fwupdate-efi-10-6.fc28.x86_64.rpm
efivar-34-1.fc28.x86_64.rpm
efibootmgr-15-6.fc28.x86_64.rpm
Maybe its quicker to google them?
Anyway, once you have them go into the terminal and type:
sudo dnf install <name of="" package=""> one by one, reboot and pray.