Binary package hint: grub2
The following line in /etc/grub.d/10_linux is present in Natty but not Maverick:
GRUB_CMDLINE_EXTRA="$GRUB_CMDLINE_EXTRA vt.handoff=7"
That creates seamless transition to the graphical login screen. Specifically, it makes the 7th virtual terminal come up automatically, so you don't see the console login prompt before X11 loads. This is a good thing. The problem is that this occurs even when X11 is not installed! The result is that a command-line system will appear to have failed to boot, showing a blank, purple-tinted screen (on tty7) instead of the console login prompt on tty1. In order to log in and use the system, the user must manually switch to one the usable virtual terminals (tty1 through tty6).
When X11 is not installed, grub2 should not be configured with vt.handoff=7. A weak fix for this problem would be for Ubuntu installations not providing X11 not to include that line in /etc/grub.d/10_linux (or, better, to include it, commented out, with a comment explaining what it does). A strong fix for this problem would, in addition, cause that line to be added (or uncommented) when X11 is installed (or when it's reconfigured to provide a graphical login screen), and removed (or commented out) when X11 is uninstalled (or when it's reconfigured not to provide a graphical login screen).
These were the steps I took, which produced the bug:
(1) Install a command-line system from the Natty Alpha 1 i386 Alternate Install CD. (At the boot menu, after selecting the language, press F4, and a command-line system is one of the options.)
(2) When the system boots, observe the blank purple screen. Switch to usable virtual terminals with Alt+F1 through Alt+F6. (Switching back to tty7 shows the same blank screen, but it is no longer tinted purple.)
(3) Log in, update the package cache, and install all available updates (I used apt-get for this), allowing new versions of any systemwide configuration files to replace the current versions. Reboot.
(4) Repeat step 2, confirming that this bug has not been fixed by the updates.
And then these were the steps I took, to confirm my analysis of the bug:
(1) Edit /etc/grub.d/10_linux (e.g. "sudo nano -w /etc/grub.d/10_linux") and comment out the line containing "vt.handoff", or change the number from 7 to some lower number. (I tried it both ways; they both worked.)
(2) Run "sudo update-grub" to apply the new configuration.
(3) Reboot. A usable virtual terminal with a login prompt comes up automatically.
ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: grub-common 1.99~20101221-1ubuntu2
ProcVersionSignature: Ubuntu 2.6.37-11.25-generic 2.6.37-rc7
Uname: Linux 2.6.37-11-generic i686
Architecture: i386
Date: Thu Dec 30 05:45:46 2010
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha i386 (20101202)
ProcEnviron:
LANG=en_US.UTF-8
LC_MESSAGES=en_US.utf8
SHELL=/bin/bash
SourcePackage: grub2
I am able to reproduce this bug (and the workaround) on Natty Server (installed from the Alpha 1 Server Install CD). Since Ubuntu Server is configured by default to write status information to tty7, it looks a little different -- you see a "shadow" of whatever text is written there.
Arguably the unreadability of that text could be considered an additional bug, but I don't think so. Switching to any other virtual terminal and back renders the text readable again (because it gets rid of the purple color scheme, just as on an Ubuntu non-server command-line system). When the workaround is applied, text on tty7 is always readable.
On the other hand, a minority of server administrators might prefer to see those status messages (instead of a login screen) when they boot up their servers. Assuming they haven't installed X11 (or have, but have it configured not to provide a graphical login screen), they could achieve this by manually adding vt.handoff=7 to the grub2 configuration.