I'm not sure many inexperienced users are also dual-booting another distribution. And also Fedora's dual boot support is limited to installing along side an existing Windows or macOS installation.

We're sorta stuck in a catch-22. GRUB multiboot is upstream territory but then distributions end up creating mutually incompatible forks of GRUB, periodically rebasing to upstream. Further, in either a Secure Boot or measured boot regimes, Fedora's GRUB can't directly boot another distribution anyway. Fedora's bootloader only contain the kernel signing key used to verify Fedora kernels. And measured boot verifies boot chain hasn't been tampered with to permit the unsealing of crypo keys so that boot can proceed. An intermediate bootloader from another distro is indistinguishable from an attack on the boot chain.

The firmware's built-in boot manager (boot selection, alternate boot device, etc.) is now the primary interface for multiboot, I think. :person_frowning:

I have dual boot. However, I disabled the Windows disk before installing Fedora so the Windows entry wouldn't appear in Grub and I still have the old kernels showing:

That's normal. By default Fedora keeps three kernel boot entries, plus a rescue (initramfs) entry.

Workstation WG discussed this at yesterday's meeting. There are a few issues.

• Fedora only shows a max of three kernels by default, and by default the GRUB menu is hidden. We're not convinced there's a UI/UX problem here, and in any case it's a question for upstream to take up.

• Multibooting other Linux distros isn't supported by Fedora, in that there's no release blocking criteria requiring it. Not even side by side installations of Fedora. But insofar as GRUB supporting this in a UEFI Secure Boot context; and likely related, GRUB supporting dualboot with Windows Bitlocker enabled (due to measured boot and TPM enablement) which is a priority for the Workstation WG, I opened an inquiry upstream: https://lists.gnu.org/archive/html/grub-devel/2022-05/msg00057.html

• GRUB currently has a fwsetup command, which we expose by default in the GRUB menu as a user visible entry "UEFI Firmware Settings". Could there be a command that provides "UEFI Boot Manager" so users can more easily get into the built-in boot manager, a.k.a. boot selection, a.k.a. boot order?
  https://lists.gnu.org/archive/html/grub-devel/2022-05/msg00059.html

I agree that, in the multi boot case, showing old kernels in the boot list is potentially confusing and not what we really want for our dual boot experience.

We do have some old boot menu mockups, which use a submenu for old kernels:

That said, I agree that this is best dealt with upstream.