View Full Version : [ubuntu] Encrypted LVM Blank Screen for password

January 21st, 2012, 10:48 AM
Hi everyone,

I am having the following problem:

After a fresh install of 64 bit encrypted LVM Ubuntu, grub complains with "Error: No video mode activated", and doesn't display the password prompt for LVM. I can type it in "in the dark" and if I don't make any mistakes, it then boots fine.

I was able to avoid video mode all together by uncommenting "GRUB_TERMINAL=console" in /etc/default/grub and do a "sudo update-grub", however, that would only display the grub boot options, the LVM screen was still black.

This seems to be related to http://ubuntuforums.org/showthread.php?t=1762702, although that thread is now quite old.

Interestingly, I did an install of 32 bit, exactly same setup, a few hours earlier, and it worked fine. Although that previous install was of a CD, and the second of a USB disk with the 64 bit alternative installer iso. But then I figure since I have run update-grub a couple of times at least my grub must be in the right place...

Anyway, does anyone have an idea for a fix? Or alternatively, can I force LVM to use the console? Ctrl+Alt+F1 and so forth had no effect.


March 11th, 2012, 04:08 PM
I would like to get help with the same issue.

Just installed 64 bit 12.04 and have the same problem. I found the solution to resolve the error, but the enctyption password screen is blank.


March 11th, 2012, 07:11 PM
I just think of it as an extra security feature.
If an attacker doesn't know they're supposed to type a password, it would likely delay them indefinitely. However, I know to give the OS a minute or so after the GRUB Menu and then try typing my password. :)

March 29th, 2012, 04:28 PM
So, it appears that I may have resolved my issue. In my case, I am using a brand new Dell 6420 laptop with an Nvidia graphics card. I installed the proprietary driver (for a different reason) and now I am able to see the encryption password screen on boot. It may be this is a problem with the open source video driver.

Herman, I decided to look at the issue the same way you did and was just going to live with it.

March 29th, 2012, 08:30 PM
Aha! That's very interesting ti1ion, and that reminded me of something else as well.

Here is a link to an very well written how to from back in the GRUB Legacy days, HOWTO: Change bootup resolution (http://www.ubuntuforums.org/showthread.php?t=258484&highlight=kernel+booting+parameters).

I'm not too sure if there's a newer equivalent to that excellent how-to around anywhere, (updated for GRUB2 and more recent versions of Ubuntu). I imagine much of the information there would still apply or at least I think it's still worth a read.