Fedora/CentOS/RHEL boot only from this grub. When install Fedora and CentOS, CentOS no boot from Fedora boot loader, Fedora no boot From CentOS boot loader. Why?
On Nov 15, 2023, at 11:33, fedoraUser 2023 fedorauser86@gmail.com wrote:
Fedora/CentOS/RHEL boot only from this grub. When install Fedora and CentOS, CentOS no boot from Fedora boot loader, Fedora no boot From CentOS boot loader. Why?
I can think of one reason: On UEFI systems with secure boot enabled, the Fedora shim can’t boot CentOS or RHEL-signed kernels.
From what I understand, it’s best to just boot the signed bootloader for each OS rather than try to make one boot them all.
Secure boot is off.
On Wed, Nov 15, 2023 at 11:33 AM fedoraUser 2023 fedorauser86@gmail.com wrote:
Fedora/CentOS/RHEL boot only from this grub. When install Fedora and CentOS, CentOS no boot from Fedora boot loader, Fedora no boot From CentOS boot loader. Why?
Have you updated GRUB recently?
As I understand things, GRUB is not updated automatically. Once installed, it has to be updated manually. In fact, it is an option upgrade step at https://docs.fedoraproject.org/en-US/quick-docs/upgrading-fedora-offline/#sect-update-grub-bootloader-on-bios.
And there's the forbidden signature database that blacklists buggy versions of GRUB... https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html/managing_monitoring_and_updating_the_kernel/updating-the-secure-boot-revocation-list_managing-monitoring-and-updating-the-kernel.
Jeff
On Nov 16, 2023, at 03:02, Jeffrey Walton noloader@gmail.com wrote:
On Wed, Nov 15, 2023 at 11:33 AM fedoraUser 2023 fedorauser86@gmail.com wrote:
Fedora/CentOS/RHEL boot only from this grub. When install Fedora and CentOS, CentOS no boot from Fedora boot loader, Fedora no boot From CentOS boot loader. Why?
Have you updated GRUB recently?
As I understand things, GRUB is not updated automatically. Once installed, it has to be updated manually. In fact, it is an option upgrade step at https://docs.fedoraproject.org/en-US/quick-docs/upgrading-fedora-offline/#sect-update-grub-bootloader-on-bios.
Nope, you don’t need to touch the grub configuration once installed on a Fedora system unless you have changed the settings in /etc/sysconfig/grub or you’ve updated to a new Fedora release (and that’s done automatically, I believe).
New kernels drop a file in /boot/loader/entries/ as part of the post-install script, and those files are read by grub during boot.
Now there have been people who post to this list that have managed to mess up their system to the point where they have to manually run grub2-mkconfig after each kernel update, but that’s not the default behavior of Fedora.
And there's the forbidden signature database that blacklists buggy versions of GRUB... https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html/managing_monitoring_and_updating_the_kernel/updating-the-secure-boot-revocation-list_managing-monitoring-and-updating-the-kernel.
This is something you’d get as a firmware update, either through fwupd, a windows update (dual-boot) or by manually updating the BIOS/firmware though some out-of-bound method. DBX updates change the firmware and not grub2.
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fedoraUser 2023 -
Jeffrey Walton -
Jonathan Billings