I have installed Fedora 25 on an Ubuntu 16.04 system for dual boot. The system boots by default to the Ubuntu partition. The GRUB menu, however, does not show an entry for Fedora.
Fedora was installed with default settings on unoccupied space on my HDD. This means that its partition was configured to be LVM. Is this why GRUB can't see it? How do I add an entry for Fedora?
Ubuntu does not have the LVM driver installed unless you have Ubuntu using LVM. And then it cannot see the Fedora install.
# to find an LVM install from a non-LVM install
sudo apt-get install lvm2
sudo vgchange -a y
sudo update-grub
More info:
How do I triple-boot Ubuntu, Fedora and Windows 7?
One of the advantages of LVM is total management of the entire drive. So if multi-booting and not installing all installs inside the LVM, often then better to install Fedora in a standard ext4 partition.
Advantages/Disadvantages LVM Post #9
http://ubuntuforums.org/showthread.php?t=1586328&p=9917145#post9917145
If Fedora was installed after Ubuntu then it's likely that when installing Fedora decided not to modify the boot configuration, since Grub was already there. Boot into Ubuntu and run sudo update-grub to force the boot configuration to be rewritten which should cause your Fedora partition to be discovered.
