Fix error symbol grub_calloc not found

… by restoring GRUB for crypted disks

After system update and reboot, GRUB failed with this error symbol 'grub_calloc' not found.

• fix it with these commands

fsck /dev/nvme0n1p*
efibootmgr -c --disk /dev/nvme0n1
efibootmgr -v /dev/nvme0n1

• check in your BIOS if EFI boot is always configured (link to /boot/efi/EFI/arch/grubx64.efi)

• in bonus, if you want to mount your crypted system

cryptsetup open /dev/nvme0n1p3 data
pvs
vgs
vgchange -ay
lsblk -fs
mount /dev/mapper/arch-root /mnt/
mount /dev/mapper/arch-home /mnt/home/
mount /dev/nvme0n1p2 /mnt/boot/
mount /dev/nvme0n1p1 /mnt/boot/efi/                                                # for UEFI systems
arch-chroot /mnt

• GRUB by Archlinux Wiki