Unlock LUKS encrypted Debian root with key file on boot partition

I'm trying to decrypt the Debian root with a key file stored in the boot partition (decrypted partition). This will break the security, but it doesn't matter now. I have to conclude this successfully or die trying. I have created the hooks to the initramfs and the key file is on the /boot directory inside the initrd.img-* file. The path to the key file (/boot/keyfile) is on the /etc/crypttab file. I updated the initramfs with sudo update-initramfs -u but I received this message: cryptsetup: WARNING: target sdaX_crypt uses a key file, skipped. Ignoring the message and rebooting results in a unbootable disk. The message Gave up waiting for root device. is displayed and drops to initramfs shell. In the initramfs environment the cryptsetup don't exists. *(It should exists?)* Seens that the update-initramfs -u "thinks" the sdaX_crypt device will be mounted in another way and don't configure to decrypt with the keyfile. *How can I do that?*