Boot precautions; recommendation?

[alquimista.ndc]

Hi,

I have been using Linux distributions for several years now in my main personal PC. I always have had a partition configuration like this:
1- Main Linux partition boot
2- Secondary Linux partition boot
3- My Data partition

In 1, currently I have Kubuntu. In 2, I always keep Mint. In 3, is my user's data. A couple of days ago, this partition setup saved me, as the Kernel update failed in partition 1, and I could manage to work under Mint. I later found out that I could work under a previous kernel in partition 1, selecting it from the Grub menu.

Recently, I installed Kubuntu in a HP zBook 14u G4. The whole HD with Kubuntu, and all is just perfect. So obviously, I don't get into a grub menu in the laptop, as Kubuntu is the only one distro there. But, if I run in a similar situation as in my PC, where the latest kernel fails in the laptop... how can I get to load a previous kernel? is there an FX key I may press to come up with a boot menu and select the kernel I need to boot with? Or should I partition the laptop as I have my PC, in case of a Kubuntu boot contingency?

[oshunluvr]

Grub is still loading, it's just doing it with a hidden menu. You can un-hide it by changing the defaults or by holding the SHIFT or ESC key during boot. Which one depends on your setup and timing.

In any case, IMO having a backup distro is never a bad idea if you have the space - jus' sayin'. Never know when you'll bork your system. Alternately, have a bootable USB handy.

[claydoh]

Stabbing the esc key just past the bios/logo splash should bring up the grub menu, tho that is tricky for me if I get the timing wrong, as this also can open my PC's bios menu if I do it too early.
You can tweak grub to always show, as well, or change the timeout from 0 to a few seconds.
Grub-customizer should be useful for this.

[Fred47]

I do what you are doing, the whole drive is devoted to Kubuntu. If something goes wrong I'll boot to Knoppix on a USB drive and fix my problems from there. https://www.techrepublic.com/blog/di...-distribution/

[jlittle]

(Note that with a modern PC, there should be a small EFI System Partition.)

An alternative to another partition for another install, is to use a big btrfs partition, with several installs in it. That way, one doesn't have to juggle space between the different installs, and data directories. Separation is done with subvolumes.

[Teunis]

In the past I've been bitten by having a single /home shared by two different installs (with their own root)
Because different versions will likely want to save different configurations in that /home/.* potentially overwriting the other one.

So since many years I give each their own /home but link things like ./mozilla and ./thunderbird from the main to the secondary /home.

Even that isn't totally foolproof as recently seen with Firefox that had been updated using Neon was marked as a incompatible version when opening it on Kubuntu 20.04.
Also updating Firefox on 20.04 solved the problem.