[MULTI BOOT] [ABANDONED] One grub too many in a dual boot of Kubuntu 22.04 and Linux Mint Cinnamon 21.1

[ineuw]

LMC 21.1 was the first Linux installation on a dedicated 128MB SSD. Then, I added another SSD drive dedicated to Kubuntu 22.04. Now, grub boots from the Linux Mint grub and I would like to transfer everything to the KU22.04 drive and leave only the minimal grub necessary on LMC.

Where can I find instructions to accomplish this? I have the necessary grub and boot management software installed in both, as well as the USB live keys.

[Qqmike]

If you boot into Kubuntu and issue two commands at Konsole, then your computer should boot into Kubuntu first, and there should be an option at that point to boot into Mint.
Those two commands (for a (modern) UEFI system) are:

sudo grub-install
sudo update-grub

[jlittle]

Qqmike is correct, but if you keep the Mint install updated, the next time the Mint grub is updated, it will take control of the boot again. Solutions, in Mint

1. uninstall all grub packages
2. install grub-efi-amd64-bin; it will say it is already installed, but might mark it as manually installed, and uninstall grub-efi-amd64

1, is simpler, but 2. might be useful if you trash the Kubuntu install.

[ineuw]

Thanks for the replies.

I have a triple boot system in which each OS is on a separate 128GB SSD and two non bootable data drives.

For my sanity and clarity, I followed the SATA connection order with the 5 drives, which may affect my attempts since the UEFI follows this order, indicatig Ubuntu SATA1. . . , etc.

sda Linux Mint Cinnamon 21.1
sdb Windows 11
sdc data drive
sdd data drive
sde Kubuntu 22.04

Kubuntu was installed while the other drives were disconnected. This way a drive can be removed and used as an external USB3 connected drive, if a permanent installation is not wanted. That is how there are two grub installs. After reconnecting the other drives, I used boot-repair with a USB live key and tried making the Kubuntu installation to be the active grub, but the system keeps using the grub with Linux Mint. Grub Customizer was used to set the desired boot order Ku, LM, Windows.

At this point, following @Qqmike's, advice, I removed the Grub files from Kubuntu, and will now reboot. Thanks again.

[claydoh]

Another option to nuking existing grubs installs is to set the desired OS as the first boot choice in your BIOS.
This is sort of your 'primary' OS if you will.
The only time an OS other than Windows will take over and set itself as the first boot device is during an install.
Normal updates don't reset the boot order.
Windows of course can do this.
This preserves boot options in the event one OS goes south. Just select a different one via boot time hotkeys, or change the order in the BIOS.
The downside is that those other OS installs won't be aware of kernel changes or new OS installs until their own grub is updated.

But oh my, this is soooo much simpler than MBR bootloaders, chainloading, and primary/extended partitions.
I remember once having 7 installs on one system with this (just to see). It was quite fragile after a while if I recall clearly.

[ineuw]

Will waste no more time of our retirement years on this issue. A fresh install is a lot quicker because of damage done and none of the restores fixed it. Thanks to all.