Reinstall GRUB and Kernels

lsblk -f

Explanation This lists all disks, including:

• LUKS encrypted root partition
• EFI partition (usually FAT32)
• /boot partition (ext4 or similar)

Unlock Your LUKS Root Partition

sudo cryptsetup luksOpen /dev/sdXN cryptroot

Explanation

• /dev/sdXN → your encrypted root partition
• cryptroot → name for the unlocked mapper device

After unlocking, it appears as: /dev/mapper/cryptroot

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sudo mount /dev/mapper/cryptroot /mnt

Explanation This mounts your decrypted root filesystem to /mnt.

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sudo mount /dev/sdXY /mnt/boot

Explanation Mount the separate /boot partition so kernels and initramfs can be written.

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sudo mount /dev/sdXZ /mnt/boot/efi

Explanation Mount the FAT32 EFI partition so GRUB can reinstall its EFI files.

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for i in /dev /dev/pts /proc /sys /run; do
  sudo mount --bind $i /mnt$i
done

Explanation This makes the chroot environment act like a real running system.

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sudo chroot /mnt

Explanation You are now "inside" your installed Arch system as root.

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pacman -Syu

Explanation Refresh the package database and update installed packages. Ensures kernel and GRUB reinstall cleanly.

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pacman -S linux linux-headers
pacman -S linux-lts linux-lts-headers

Explanation

• linux → latest Arch kernel
• linux-lts → stable long-term support kernel

Headers are required for DKMS modules.

Having both gives redundancy.

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mkinitcpio -P

Explanation

• Rebuilds initramfs for every installed kernel
• Ensures correct LUKS hooks are included

Equivalent to rebuilding:

• initramfs-linux.img
• initramfs-linux-fallback.img
• initramfs-linux-lts.img
• initramfs-linux-lts-fallback.img

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grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=GRUB

Explanation

• Installs GRUB into the EFI System Partition
• Creates a new UEFI boot entry

This fixes any broken signature or missing GRUB binaries.

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grub-mkconfig -o /boot/grub/grub.cfg

Explanation GRUB scans:

• the latest kernel
• the LTS kernel
• fallback initramfs images
• your LUKS setup

Generates a new boot menu.

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exit
for i in /dev/pts /dev /proc /sys /run; do
  sudo umount /mnt$i
done
sudo umount /mnt/boot/efi
sudo umount /mnt/boot
sudo umount /mnt
sudo cryptsetup luksClose cryptroot

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reboot

You should now see GRUB with:

• Arch Linux (Latest Kernel)
• Arch Linux (LTS Kernel)
• Fallback images

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Your /etc/mkinitcpio.conf must contain:

HOOKS=(base udev autodetect modconf block encrypt filesystems keyboard fsck)

If changed:

mkinitcpio -P