I have the same issue after upgrade Ubuntu 14.04 - Ubuntu 14.10.
I get black screen during boot.
Workaround: Alt+F1 (to get a screen with text cursor) and then Alt+F7. Then I
can enter passphrase for my encrypted partition and continue in boot.
For me it's a regression in kernel 3.16 because it
** Description changed:
I am iso-testing the current lubuntu-amd64-alt iso. in a VM. After
doing an encrypted install, when the machine reboots you see only a
black screen. Pressing alt-f7 will display the passphrase challenge and
if correctly entered the machine will boot normally.
