Why can't I change root under rescue mode?

Question

linux

Can't get root on new debian installation, hoster (soyoustart) gives only debian user.

Booting into rescue mode

lsblk
mount /dev/md2 /mnt
chroot /mnt
passwd root
exit
umount /mnt

Next, boot into HDD mode.
And nothing. Access denied.

Answer 1

sudo -s will take you to root level