How do I set up LUKS full disk encryption on Kubuntu?

[Tenderiser]

So I'm trying to install Kubuntu will full encryption and manual partitioning.

I try:
1024MB FAT32 partition with /boot/efi flagged as "boot"
1024MB Ext4 partition with /boot
142GB Ext4 LUKS partition with root

It gives me a warning "Boot partition not encrypted", tells me it's insecure and I should encrypt it.

So I delete that partition and just have the following (since I don't need the boot partition separate if it's not unencrypted):
1024MB FAT32 partition with /boot/efi flagged as "boot"
143GB Ext4 LUKS partition with root

After I install and reboot, GRUB doesn't detect anything and the various remediation steps I tried don't seem to work on Kubuntu.

Anyone know how I go about setting this up?

[Snowhog]

Maybe see https://www.kubuntuforums.net/forum/...4-10-with-luks

Welcome to KFN!

[Tenderiser]

Maybe see https://www.kubuntuforums.net/forum/...4-10-with-luks

Welcome to KFN!

That post didn't come up in my searches so thanks for bringing it up, but it's not really helpful. Their solution was to use the erase disk option but I need manual partitioning because I want to leave half my drive for dual-boot.

[claydoh]

Just let the installer take care of it for you?
Maybe the /boot is too small, and the installer doesn't like that?





25.04 here doesn't gripe about the apparently unencrypted /boot, and the process and layout used would be the same if shrinking Windows or another OS, other than sharing the existing EFI partition.




Hmm... are you trying to install 24.04? This might be helpful.
I do think that this is a warning message you see when manually setting things up, but the installer would still proceed, just like it does if you make the EFI partition smaller than 300Mb.

I did not see any warnings with 25.04 here, using automatic partitioning.