Adding Fedora 40 to existing Grub 2.x can it be done?

Ask Fedora
1

This is a noob question.

I wanted to dual boot between Linux Mint 21.3 and Fedora 40 on the same SSD using a common /home directory. But since Mint was already installed and it appeared that both used Grub 2.x, I thought I’d install Fedora without the bootloader and add the grub menu entry later on using OSProber and update-grub command.

So I booted into Mint, used the command and it added entries for Fedora to the grub menu. But when I try to use them, I get an error that I need to load the kernel first. The entries for Linux Mint still work though.

Secure boot is NOT enabled on this machine.

Is it possible to add the correct entries for Fedora? And if so, how?

Thanks in advance.

2

You need something like this for your fedora entry.
You will need to edit to use the names of your disks and set the arch (this is from an AM VM).

title Fedora Linux (6.10.3-200.fc40.aarch64) 40 (KDE Plasma)
version 6.10.3-200.fc40.aarch64
linux /vmlinuz-6.10.3-200.fc40.aarch64
initrd /initramfs-6.10.3-200.fc40.aarch64.img
options root=UUID=93c96a90-cc18-4b79-a2cf-72cd79f970bf ro rootflags=subvol=root rhgb quiet```
3

This is fine when sharing a common home with multiple systems using the same OS and release version, but may encounter conflicts between with various user configuration files that differ across distros (or release versions). You may find it better to put directories that should be shared in something like /share and have small /home directories for each distro with symbolic links to the shared directories.

Edit: I should mention that rather than rebooting to switch distros, you can put one distro in a VM so it is accessible from the other distro without the need to reboot.

1 Like
4

Thanks, Barry. So to clarify I need to adapt this entry for Fedora in the grub configuration file?

I guess that means I need to but from the install media in order to edit this on the boot partition?

5

If mint uses a monalithic grub config yes,
If mint uses BLS add a entry file.

Not sure what you are asking. Are you asking how do you update /boot?
I guess you can do that from mint.

6

Well. I had a typo. “But” was supposed to be “boot”. I was under the impression that to safely backup and edit grub entries on the boot partition it would be best to do it from a drive (like a USB Flash drive) that wasn’t running the OS.

I will look for a resource covering this.