My problem was the kernel configuration, it lacked a certain number of modules that should be compiled in static.
I did not install grub, I modified the grub from my host to keep the start of my Debian.
My problem now is the netnork, indeed, I haven't network on my LFS even if my eth0 interface is recognized. I see the problem, I am on vmware virtual machine, I must install the vmware tools but it's another problem.
Thank you very much for your advices Druuna.