Hello, Ive just installed ubuntu and chose to encrypt it. However, when I am asked to enter my passphrase, display switches between ubuntu logo and space for entering the passphrase and black background resembling terminal where stars also appear. These two things switch after entering 2-3 characters ("ubuntu page" disappears and "black page with plain text" appears and vice versa). There is also different number of "stars" on each of them. They switch so rapidly I am unable to write whole passphrase in one place so it is impossible to unlock my computer. I am writing this post from another PC. Can this be fixed or do i need to install ubuntu without encryption?