I installed Fedora23 on a GPT partition(also chose LVM option).
There is no option now for Ubuntu on the GRUB list when I boot normally (without interfering). However, if I hit F9 on bootup and go into boot options, I see
Fedora(Toshiba MQ01...) Ubuntu(Toshiba MQ01..) Boot From EFI File
I can boot from here to Ubuntu by selecting Ubuntu or going into the EFI(grubx64.efi).
update-grub from Ubuntu.
I also followed the instructions from Fedora Wiki.
When I run
grub2-mkconfig -o /boot/grub2/grub.cfg, I can see Ubuntu 14.0.. on /dev/sda5
Found linux image: /boot/vmlinuz.... Found initrd image: /boot/initramfs-4..... Found Ubuntu 14.04... on /dev/sda5
But I don't have an Ubuntu option to boot.
What can I change to have the options for both Fedora and Ubuntu?
As suggested by clearkimura, I ran update-grub in Fedora first.