Hello all
I’ve been reading around as I’m trying to install a new distro to an partition that already has a Ubuntu version. I’ve read that the grub shouldn’t be installed in the main partition or /dev/sda but on the /root partition where the first distro was installed?
Thanks in advance.
Whenever I have faced this problem I always log in with a live cd. I then install boot repair in the live session.
https://help.ubuntu.com/community/Boot-Repair
Install it, start it and then run “recommended repair” and let it work its magic!
Then when you log out of the live cd and back into your main machine, you will have a grub menu that shows all of the available OS’s on your machine
Which partition would be the correct then to install or point the boot loader to when installing a new distro, same as usual dev/sda or the /root partition? I’ve read mixed instructions.
Much appreciate it, I’ll give that a shot and report back.
To be honest, I have never checked. The boot repair programme is programmed, presumably, to make a sensible choice. It has never failed me to this point.
It is possible to omit installation of a second GRUB bootloader on the second distro, since only one bootloader is needed to start an operating system.
If that distro is Ubuntu-diverted and/or uses ubiquity, start the installer from a live session terminal:
ubiquity -b
or
ubiquity --no-bootloader
I haven't tested this to be certain - the first GRUB usually automatically detects other OSes and be configured to boot from them if not. Or, following @stevecook172001's advice, can be easily configured to do so with boot-repair.
If you have Windows installed, install Grub to sda which is where the MBR is located and you can’t really go wrong!. 
So I did, chose / as the root partition my second as /home and selected dev/sda as the location. Everything went smoothly, not sure if it’s because I formatted both partitions when installing the new distro but everything went smooth.
The new distro installed it’s grub and it comes up upon booting as expected. Thanks a bunch.