I had recently purchased a new PC and installed Windows and Ubuntu 16.04 on the SSD drive, sda. Since I needed to install Fedora25 as well and as my budget allowed me to purchase only a 240GB SSD, I had bought a 2TB hard disk to do that.Now, using a live USB stick, I have installed Fedora25 on the 2TB hard disk, sdb. I had chosen to create a LVM physical volume instead of the standard partition during installation. Post-installation, a successful one, I rebooted the PC and though the grub2 menu appears, it is not the one with Fedora25, but the same old Ubuntu 16.04's grub2. But, when I press boot options key F11 (MSI motherboard), I can see the Fedora25 partition's presence. When I proceed to select it and press Enter key, Fedora's grub clearly displays Fedora25, Ubuntu 16.04, Windows et al! Even so, I'm unable to boot into Ubuntu 16.04. I get the following if I try that:error: can't find command 'linux'error: can't find command 'initrd'Press any key to continue...I am able to boot Windows though.I would like to know:How can I get Fedora25's grub2 menu to show up by default and avoid getting the above errors? Is this a partition mount issue/problem?Is the LVM physical volume causing problems here? Would there have been less problems if I had chosen standard partitioning during Fedora25's installation?Is it not possible to run multiple OS on two different hard disks? Or rather enable grub2 to show all available OS installed across different hard disks implicitly during bootup and choose the desired one to boot?
How to combine grub2 of Ubuntu 16.04 on /dev/sda and Fedora25 on a LVM partition in /dev/sdb
grub2;partition;lvm;fedora