I do as the following
- run grub-mkpasswd-pbkdf2 to get a string
- nano /boot/grub/grub.cfg
- add tow lines
- set superusers="putyourusernamehere"
- password putyourusernamehere grub.pbkdf2 (omitted)
When i reopen my computer,it can't work,how can i take grub 2 Password Protection in debian ?