2025 / 10 / 11

Unable to boot into Manjaro encrypted device after update

After updating my OS last night I was seeing this error after reboot:

Error: grub_is_using_legacy_shim_lock_protocol not found

Yup, didn’t read the update/release notes (as usual). So needed to do some digging around until I found a solution that worked for me.

My OS is installed in sda, so there are two partition in it: sda1 (boot, EFI System) and sda2 (the encrypted device, Linux filesystem).

Since I’m using LUKS encryption there were some steps I needed to follow to fix my OS:

1. First, boot using a Manjaro live USB stick (so I’m able to type commands and access my boot and my encrypted partition).

2. Go into a terminal and open the encrypted partition (for me it’d be sda2):

    sudo cryptsetup open /dev/sda2 a2

3. Mount it:

    sudo mount /dev/mapper/a2 /mnt

4. Create mount point for the boot/EFI partition:

    sudo mkdir -p /mnt/boot/efi

5. Mount the problematic boot partition there (sda1 in this case):

    sudo mount /dev/sda1 /mnt/boot/efi

6. Log in with manjaro-chroot:

    sudo manjaro-chroot /mnt

7. Install grub:

    install-grub

8. Exit, unmount everything and reboot:

    exit
    sudo umount -R /mnt
    sudo shutdown -r now

That’s it. Hopefully it’ll help someone else.

References

• Get a black screen with “Error: grub_is_using_legacy_shim_lock_protocol not found”