Arch Linux

fluttershy

Member

Registered: 2014-04-14

Posts: 6

Kernel 7: Boot failure with LUKS root partition (timeout on /dev/mappe

Hello,

I’d like to share a quick experience report in case others run into the same issue.

After upgrading my system from kernel 6 to kernel 7, booting from my encrypted root partition stopped working. During startup, I received the following error:

timed out waiting for device /dev/mapper/vg-root

Since my installation is a few years old, I noticed that the device was still referenced by its name instead of a UUID:

/etc/default/grub:

GRUB_CMDLINE_LINUX="cryptdevice=/dev/nvme0n1p2:vg root=/dev/mapper/vg-root ..."

At first, I thought the device name nvme0n1p2 had changed, but that wasn’t the case. It seems that something has changed so that this no longer works; whether that’s intentional or a bug is unclear. I couldn’t find any information on it. In general, the approach described below is the better way to configure this anyway.

Solution:

Switching to a UUID-based configuration resolved the issue:

GRUB_CMDLINE_LINUX="cryptdevice=UUID=device-UUID:vg root=/dev/mapper/vg-root ..."

(Replace device-UUID with the actual UUID of your device.)

For more details on configuration differences depending on whether you use encrypt or sd-encrypt, see:

2.5 Configuring mkinitcpio
2.6 Configuring the boot loader

After making this change, the system booted normally again.

Hopefully this helps others running into the same issue. If anyone has more insight into whether this change is intentional, I’d be interested to hear it.

Last edited by fluttershy (2026-05-03 07:56:34)

frostschutz

Member

Registered: 2013-11-15

Posts: 1,647

Re: Kernel 7: Boot failure with LUKS root partition (timeout on /dev/mappe

Do you have multiple nvme devices? It's normal for sda,sdb,sdc or nvme0,nvme1,nvme2 to randomly switch places, so using UUID or LABEL is pretty much mandatory.

fluttershy

Member

Registered: 2014-04-14

Posts: 6

Re: Kernel 7: Boot failure with LUKS root partition (timeout on /dev/mappe

Hello,

i have only one nvme device. My current blkid output:

[~]$  blkid 
/dev/mapper/vg-swap: LABEL="swap" UUID="..." TYPE="swap"
/dev/nvme0n1p1: UUID="..." BLOCK_SIZE="512" TYPE="vfat" PARTLABEL="EFI System" PARTUUID="..."
/dev/nvme0n1p2: UUID="..." TYPE="crypto_LUKS" PARTLABEL="Linux filesystem" PARTUUID="..."
/dev/mapper/vg-root: UUID="..." BLOCK_SIZE="4096" TYPE="ext4"
/dev/mapper/vg: UUID="..." TYPE="LVM2_member"

nvme0n1p1 is /boot (and not encrypted)