In order to have bcache

sudo -i
modprobe bcache
partprobe

#Now, /dev/bcache* should be present, and you can carry on mounting, reformatting, etc. from here.

for lvm2

lvmdiskscan
lvdisplay
#give you the name of the lvm2 device

mount the lvm2 in /mnt

mount boot in /mn/boot

mount efi in /mnt/boot/efi

#install chroot script
pacman -Sy arch-install-scripts
arch-chroot /mnt /bin/bash

#update mkinitcpio
mkinitcpio -p linux

or update kernel for example

pacman -Sy linux

#DONE !