How to encrypt full sd card

[seeing350]

hi all,

  I use armbian jessie on my nano pi m1, I want to encrypt full sd card, and decrypt when boot. My disk structure are:

/dev/mmcblk0p1    /boot

/dev/mmcblk0p2    /

 

it can boot normally without encrypt. After I encrypt mmcblk0p2 with cryptsetup, the booting process stopped, and  message are:

 

and it will reboot.

 

how can i fix this problem?

 

thank you for help.