Do I need GRUB2 if it's installed in another distro?

Message

patrick_mooney · Post by **patrick_mooney** » Wed Oct 04, 2017 12:35 am

First time installing Gentoo. Hello there!

I'm following through the installation sections of the Gentoo Handbook and wonder whether I really need to install a bootleader: I currently have Crunchbang++ (A Debian derivative) and Linux Mint 17.3 installed (and Windows 10, primarily because once in a while my crappy ISP tries to blame their problems on me running Linux).
I've got an EFI system partition on /dev/sda1 (and, sigh, I just discovered it has cruft from other distros I no longer run) and one of the Linux distros (though I misremember which) is currently booting the system with GRUB2. All installed operating systems are currently able to boot.

Do I really need to install GRUB2 on Gentoo, or can I just switch back to one of the other distros after the install process and run sudo apt-get update-grub with os-prober installed?

Do I need to create a new /boot partition, or can I just mount /dev/sda1 as /boot? Or should I do something else?

I'm installing on an x64 Hewlett-Packard laptop with an i5 processor.

Many thanks for any advice!

Jaglover · Post by **Jaglover** » Wed Oct 04, 2017 12:53 am

Welcome to Gentoo!

Of course one booloader is enough.

patrick_mooney · Post by **patrick_mooney** » Wed Oct 04, 2017 1:01 am

Thank you so much! That's what I thought, but wanted to make sure before proceeding.

szatox · Post by **szatox** » Wed Oct 04, 2017 2:04 pm

You can mount the same boot, and even the same home, and tmp if its big enough to be on disk. Swap can be shared too (if you have it at all).

Roman_Gruber · Post by **Roman_Gruber** » Thu Oct 05, 2017 12:37 pm

Do I really need to install GRUB2 on Gentoo, or can I just switch back to one of the other distros after the install process and run sudo apt-get update-grub with os-prober installed?

MY bootloader is from linux mint

I just edit the boot entries by hand. there is no need to reinstall grub / update grub. Most of the time for the gentoo part is just to copy over the bootfiles and change the kernel name in my boot entry. Many bootloaders just utilize a textfile which can be edited by an editor.

When my UEFI forgets the mapping uefi to my harddrive i reinstall grub with sysrescue-cd. that happens only sometimes

limn · Post by **limn** » Thu Oct 05, 2017 2:24 pm

If grub is installed in Debian, it automatically runs when a new kernel or initrd.img is installed.
In some cases is it is preferable to have only one distro managing grub.