Arch Linux

copperminda

Member

Registered: 2025-05-24

Posts: 2

Windows dualboot on existing LUKS+LVM btrfs Arch installation

I need to install Windows dualboot alongside existing Arch system with LUKS+LVM setup. I'v been tinkering with hibernation support so also I have encrypted swap (that was the hardest part, not straightforward process). I don't remember how I did it lol so I'm not sure if I'll be able to reproduce grub configuration once it will be destroyed by Windows installation.

Pls help, how should I proceed to install Windows 11, restore grub and not destroy my whole system in the process?

❯ lsblk -f
NAME FSTYPE FSVER LABEL UUID                                 FSAVAIL FSUSE% MOUNTPOINTS
nvme0n1
│                                                                           
├─nvme0n1p1
│    vfat   FAT32       7209-08A1                             660.4M    35% /boot
└─nvme0n1p2
  │  crypto 2           e73d1bbf-5470-4bfc-8123-aca3fec9d3f7                
  └─crypted
     btrfs              5e740d52-6d9d-4c4b-a3fd-b0fb705bc54a  202.1G    52% /var/log
                                                                            /swap
                                                                            /home
                                                                            /.snapshots
                                                                            /

grub.cfg excerpt:

linux	/vmlinuz-linux root=UUID=5e740d52-6d9d-4c4b-a3fd-b0fb705bc54a rw rootflags=subvol=@  loglevel=3 nowatchdog quiet mem_sleep_default=deep cryptdevice=UUID=e73d1bbf-5470-4bfc-8123-aca3fec9d3f7:crypted:allow-discards root=/dev/mapper/crypted resume=UUID=5e740d52-6d9d-4c4b-a3fd-b0fb705bc54a resume_offset=1386885

resume_offset is the offset used for restoring from hibernation, however i dont remember why this value was chosen. swapfile declared size is 36G. i don't have HP points to try an attempt with ChatGPT guidelines, I'm sure that will end badly. save me

-thc

Member

Registered: 2017-03-15

Posts: 920

Re: Windows dualboot on existing LUKS+LVM btrfs Arch installation

If your system boots via EFI and the FAT32 partition is a regular EFI partition Windows should only tinker with it during the setup process and not destroy it.

copperminda

Member

Registered: 2025-05-24

Posts: 2

Re: Windows dualboot on existing LUKS+LVM btrfs Arch installation

If your system boots via EFI and the FAT32 partition is a regular EFI partition Windows should only tinker with it during the setup process and not destroy it.

you mean that existing efi grub loader will be intact and ill be able to switch between systems from EFI menu without altering grub?

SimonJ

Member

From: Alicante, Spain

Registered: 2021-05-11

Posts: 229

Website

Re: Windows dualboot on existing LUKS+LVM btrfs Arch installation

I recently installed Windows 11 alongside Arch, just to make sure I remembered how, Windows did just add an entry into the existing EFI partition and my system booted to windows by default, but all I had to do was choose Arch, from the BIOS boot options, and then change the EFI boot order, no issue afterwards.

---

Rlu: 222126

-thc

Member

Registered: 2017-03-15

Posts: 920

Re: Windows dualboot on existing LUKS+LVM btrfs Arch installation

you mean that existing efi grub loader will be intact and ill be able to switch between systems from EFI menu without altering grub?

Either that or you manually add a chainloading entry in grub for booting Windoze.