[SOLVED] Grub prompt after CentOS 8 -> RL8 migration

Development Testing
1

After my first two migrations went flawlessly in a kvm environment, but I ran into an EFI boot problem when performing the same migration on an HP Slimline. Upon the first reboot after the migration, I get dumped to a grub prompt with the message:

System BootOrder not found. Initializing defaults.
Generating boot entry “Boot0000” with label “Rocky Linux” for file “\EFI\rocky\shimx64.efi”.

Secure boot is disabled and the file mentioned above does exist.

Rebooting again, the above message goes away, but I am still left staring at a grub prompt.

This is what I did to perform the migration:

rpm -e --nodeps centos-gpg-keys centos-linux-release centos-linux-repos
rpm -ivh
https://download.rockylinux.org/pub/rocky/8.3/BaseOS/x86_64/os/Packages/rocky-release-8.3-11.el8.noarch.rpm
https://download.rockylinux.org/pub/rocky/8.3/BaseOS/x86_64/os/Packages/rocky-repos-8.3-11.el8.noarch.rpm
https://download.rockylinux.org/pub/rocky/8.3/BaseOS/x86_64/os/Packages/rocky-gpg-keys-8.3-11.el8.noarch.rpm
dnf distro-sync -y

To troubleshoot, I have followed the steps for generating a new grub.cfg and also the steps for generating an entirely new /boot folder shown here: How to Recover GRUB 2 Bootloader in CentOS 8 - CentLinux

I’ve repeated this multiple times, using the path EFI/rocky and when that didn’t help, EFI/centos.

I’ve also run across Stack exchange articles that discuss moving the files under EFI/rocky to EFI/BOOT. Didn’t help either, but I’d rather not hack my system in this manner anyway.

The good news is I’ve got a Clonezilla backup of the disk so I can startover as many times as I’d like.

Any suggestions on how I can troubleshoot this further?

2

After restoring the disk and starting over, I issued grub2-mkconfig --output=/boot/efi/EFI/rocky/grub.cfg before rebooting, and all was well. The machine boots normally now.

Adding that step to the end of the upgrade procedure:

rpm -e --nodeps centos-gpg-keys centos-linux-release centos-linux-repos
rpm -ivh
https://download.rockylinux.org/pub/rocky/8.3/BaseOS/x86_64/os/Packages/rocky-release-8.3-11.el8.noarch.rpm
https://download.rockylinux.org/pub/rocky/8.3/BaseOS/x86_64/os/Packages/rocky-repos-8.3-11.el8.noarch.rpm
https://download.rockylinux.org/pub/rocky/8.3/BaseOS/x86_64/os/Packages/rocky-gpg-keys-8.3-11.el8.noarch.rpm
dnf distro-sync -y
grub2-mkconfig --output=/boot/efi/EFI/rocky/grub.cfg
REBOOT

3 Likes
3

Does this mean conversions of CentOS 8 that are in EFI Secure Boot mode will or will not work? Does rockylinux have a signed/trusted bootloader/kernel?

4

I’m not entirely sure. I thought I read somewhere, either in this forum or on mattermost, that secure boot must be off, in order to transition properly from CentOS 8 → RL8. However, I can’t seem to find where I read that at the moment.

5

I’ve been away for a week or so, so things may have changed, but at the time the RC was released, SecureBoot was not supported. You can boot a UEFI system, but SecureBoot must be disabled.