arch-chroot -S /mnt

mkinitcpio -p linux

bootctl install

/boot/loader/loader.conf

default  arch.conf
timeout  4
console-mode max
editor   no

/boot/loader/entries/arch.conf

title   Arch Linux
linux   /vmlinuz-linux
initrd  /initramfs-linux.img
options root=UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx rw

/boot/loader/entries/arch-fallback.conf

title   Arch Linux (fallback initramfs)
linux   /vmlinuz-linux
initrd  /initramfs-linux-fallback.img
options root=UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx rw