Rootfs Encryption on Ubuntu 16.04

[pfeerick]

sorry but my intent is another, similar to automated procedure followed by
Ubuntu installer software, in which is possible to crypt all rootfs and swap partition
and decrypt them on startup.

I suggest you have a look eCryptfs then as that is the tool that Ubuntu uses to encrypt the /home partition as part of a new install.

dm-crypt and truecrypt (now veracrypt) are two other possibilities... though I don't know how you'll fare as far as getting them to work on the pine64. This guide may give you some guidance on how and what to use.