[HELP] Trouble Multi-Booting Fedora + Ubuntu

brownmustardminion@lemmy.ml to Linux@lemmy.ml – 20 points –

As the title says, I'm trying to multiboot Fedora 40 and Ubuntu 24. The documentation and guides for this all seems pretty outdated through my searching and troubleshooting.

I currently have ubuntu installed. My drive partition table looks like this:

  • sda1 -- EFI (250MB)
  • sda2 -- /boot (ext4, 2GB)
  • sda3 -- empty (ext4, 2TB) <-- Fedora partition
  • sda4 -- Ubuntu 24 (LUKS encrypted, 2TB)

I'm trying to install Fedora now and it's giving me nothing but errors. The most useful guide I found for this specific setup just has you adding sda3 as the installation path (mounted at /) for Fedora and it's supposed to figure out the EFI and boot, but that doesn't happen. In fact, the EFI and /boot partitions show up under an "Unknown" tab in the Fedora custom partition window of the installation. They should be under a tab such as "Ubuntu 24 LTS". Fedora isn't recognizing the ubuntu installation (because it's encrypted?)

Am I wrong in assuming that both OS's should be sharing the EFI and /boot partitions? Maybe that's the issue?

Anybody out there successfully dual booting Linux distros with both distros encrypted?

2

Am I wrong in assuming that both OS’s should be sharing the EFI and /boot partitions?

Shared ESP is fine as long as you don’t run out of space. Nothing in /boot should conflict but that’s not guaranteed, although having 2 potential boot partitions means having 2 potential grub configs. I’d make sda3 a ~2GB ext4 boot partition just for Fedora (mounted at /boot), and an sda5 with btrfs with a home subvolume mounted at /home, and a root subvolume mounted at /, then mount sda1 at /boot/efi (this is the default layout iirc, albeit with different partitions, ofc). This might be easier to do in the advanced blivet gui.

And yes, Linux’s boot process is a convoluted, fragile mess and there are currently multiple ongoing discussions on how to improve it.

don't share /boot

it contains stuff from the distro for booting and configuring/installing a boot loader. if both garble their stuff in there it will likely break.