Two partitions on single encrypted disk scenario


I have an unused 150 GB old disk that I’d like to use for last resort Manjaro Gnome installation and testing fields of KDE Plasma. I’d like to slice out 3 partitions: 2 would be encrypted containing Gnome and KDE installations and 3rd one would be used as swap. I tested this out already but somehow KDE overwritten Gnome entry and I couldn’t add it manually - it’s beyond my current knowledge how to do it; I’ve tried with Grub Customizer manually adding partitions IDs but no luck.

This is the issue I cannot deal myself with so I’d like to know how to achieve it and if it’s possible to do so.


Don’t. It may cause breakages, and if you’re new, it could be hard for you to recover.

I guess you installed KDE after Gnome?
If you kept the standard options, you reinstalled (and overwrote) the bootloader.
Does sudo update-grub in KDE detects also Gnome in the other partition? If yes you should see the 2 in Grub menu after rebooting.

I forgot to mention that I did also used update-grub and immediately rebooted the system - no changes were made and KDE was still only system visible in the boot manager while Gnome was overwritten.

I’m pretty sure it’s due to fact that KDE installation cannot access Gnome partition since it’s already encrypted and treat it as empty space but then, I’ve unlocked it with password and treated with another update-grub attempt but still, no luck - Gnome version wasn’t detected. I’ve proceed then with Grub Customizer trying to add entry manually typing partitions IDs but that didn’t worked either.

It’s totally possible to do a dual boot configuration when encryption is not being used (obviously) but it doesn’t seem to be possible to add encryption from third, not installed system (live USB)- unless, I’m missing something? Maybe a small encrypted grub partition should be used instead?

I’m not familiar with encryption, I’ll let more experimented ones advise you on this.
In KDE Partition Manager, do you still see the Gnome partition? Gnome grub being overwritten by KDE’s, yes, but it’s unlikely it would have wiped the Gnome system.

I guess you could still see both partitions while in a Manjaro live CD environment. Without encryption, I’d recommend some chroot within this, or reinstalling grub within KDE - and checking while grub is updated that it lists the Gnome partition.

But encryption could be tricky, I don’t know much about this and don’t want to risk borking your systems. @TriMoon, I think you could help on this topic?