On Mon, Jul 11, 2016 at 3:55 PM, Chris Murphy <lists(a)colorremedies.com> wrote:
The built-in method to discover and create menu entries for other
Linux's is suboptimal. If you update the kernel on any of those
distros, it's not reflected in the GRUB menu because each distro only
updates its own grub.cfg; and the GRUB2 way of creating menu entries
for other Linux's is done from scratch rather than pointing to the
distro specific grub.cfg. It's super annoying and upstream could fix
it but here we are...
You can use /etc/grub.d/40_custom or 41_custom (read them and then
pick whether you want to use your own drop in files or not, which I
personally think is easier and more stable long term), to add a menu
entry that points to each distro's grub.cfg using the GRUB command
"configfile" for GRUB2 grub.cfg's, and the GRUB command
"legacyconfigfile" for GRUB 0.9x grub.conf files. Now, you'll have a
GRUB menu that lists your Fedora kernels, and one entry for each
distro. If you choose a distro entry, you'll get a listing of that
distro's kernels to boot.
Or you can create a generic symlink like "vmlinuz" or "kernel" (and
"vmlinux1" or "kernel1" for an older kernel, etc) to the kernels of
the distros - in their own "/boot" directories - that don't control
grub and point at them via "40_custom".