edit /etc/mkinitcpio.conf
  setting of ram-disk for kernel

#!!! list of modules if they aren't auto-detected
MODULES=""

run
$ mkinitcpio -p linux


$ grub-install /dev/sda
  installs to MBR, not to partition

$ grub-mkconfig -o /boot/grub/grub.cfg
  
sammple output:
Generating grub.cfg ...
Found linux image: /boot/vmlinuz-linux
Found initrd image: /boot/initramfs-linux.img
  No volume groups found
  ...
done

2021
TechHut - How to Switch Arch Linux Kernels - LTS, Zen, Hardened
    https://www.youtube.com/watch?v=KbcUmAlQCHs
    https://techhut.tv/how-to-switch-arch-linux-kernels-lts-zen-hardened/
    ! sudo packman -S linux-zen