Gfilui

During software update (though Ubuntu Software Updater) in Ubuntu 16.04, suddenly the GNU GRUB screen appeared. It could not find the linux installation anymore. Following the suggestions from [1], I used 'ls' to find out where my ubuntu kernel was located: partition (hd0,2). There were many different versions there, although more vmlinuz than initrd. Since you need to have both of the same version to boot, I used the latest version for which both files were present: vmlinuz-4.4.0-108-generic and initrd.img-4.4.0-108-generic. Using the following commands

grub> set root=(hd0,2)
grub> linux /boot/vmlinuz-4.4.0-108-generic root=/dev/sda2
grub> initrd /boot/initrd.img-4.4.0-108-generic
grub> boot

I could boot my ubuntu installation. However, after login I would get a black screen. I could login to tty1 though, so following suggestions from [2] I tried running

sudo dpkg --configure -a

but this gave an error message. Then I found various posts indicating that the 108 kernel was problematic, so instead I redid the above steps in GRUB to boot the second-latest kernel, 4.4.0-97-generic. Then also dpkg --configure -a ran without any problems and generated the missing initrd images. I updated all packages with

sudo apt-get update
sudo apt-get upgrade

Then, upon reboot, GRUB could find my installation again (now version 116)!

So that's already something. However, I still get a black screen after login, which seems to be a problem with the display manager. The software is fully up-to-date now, dpkg --configure has done all it has to do, but somehow there is an issue while starting up lightdm. Following [3], I tried to install a different display manager, gdm3, but this resulted in a similar issue: instead of a black screen after login, I was simply returned to the login screen, so I still couldn't get in. I concluded it's not a lightdm issue.

As suggested in [4], I tried purging all xserver files, lightdm and plymouth, the reinstalling all, and eventually also ubuntu-desktop. This didn't resolve the black screen, so again I ran:

sudo dpkg --configure -a
sudo apt-get update
sudo apt-get upgrade -y

which upgraded some packages. But after rebooting still no luck.

Then, after reading [5], I checked the .Xauthority file and /tmp directory and all was as it should be. I also tried logging in as a guest user, but this still lead to a black screen.

So I looked into the lightdm logs at /var/log/lightdm/:

• lightdm.log doesn't show any errors




• x-0.log shows a warning:
  The XKEYBOARD keymap compiler (XKBcomp) reports:
  Warning: 'Type "ONE_LEVEL" has 1 levels, but has 2 symbols. Ignoring extra symbols.
  Errors from xkbcomp are not fatal to the X server.




• seat0-greeter.log is empty, but seat0-greeter.log.1.gz is full of warnings, the first being:
  Failed to register client: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.SessionManager was not provided by any .service files

If I manually try to startup lightdm in debug mode by typing lightdm --debug --test-mode it says "Failed to get D-Bus connection".

After login, I still get a black screen and it tells me 'System program problem detected'. I'm out of inspiration, any help would be greatly appreciated!

System information:
I'm running Ubuntu 16.04 LTS on an HP laptop with Intel core i7 processor and AMD graphics card.

lspci -vk | grep -iA15 vga shows me:

VGA comptible controller: Advanced Mircro Devices, Inc. [AMD/ATI] Chelsea XT GL [FirePro M4000] (prog-if 00 [VGA controller])
...
Kernel driver in use: radeon
Kernel modules: radeon

[1] After update in Ubuntu 16.04 I ended up in GNU GRUB and appear to be stuck there

[2] Ubuntu 16.04 LTS black screen after login

[3] https://wiki.ubuntu.com/LightDM#Help.2C_I_can.27t_see_my_Desktop.21

[4] http://helewix.com/howto/ubuntu-17-10-black-screen-solution/

[5] Ubuntu gets stuck in a login loop

Today an update caused similar symptoms on my HTPC, which is an Intel NUC box running 16.04 LTS.

I could reach my Ubuntu box via VNC but my TV display via HDMI was always black.

I am working ok now after the following steps:

xrandr -q (to see my HDMI connections are not detected)

Tested my TV and HDMI cable with a laptop, all good.
Update my way past the issue

apt-get update
apt-get upgrade

The Update forward did not fix it, time to roll back...
What kernel package is the latest we are using?

dpkg --list | grep linux-image | more

It is 4.4.0-119 so lets get rid of it:

apt-get purge linux-image-4.4.0-119-generic
apt-get purge linux-headers-4.4.0-119-generic

Reboot to check

shutdown -r now

What is the current kernel we rolled back to?

uname -a

OK lets see if 4.4.0-97 fixed it?

xrandr -q

Nope, no HDMI still.
Lets make sure are packages are OK

dpkg --configure -a

Lets try update and upgrade again...

apt-get update
apt-get upgrade

Lets try a full power down

shutdown -h now

Now lets watch the BIOS screen come up on the TV when we power the NUC box on.
BIOS displays and Ubuntu is back on my TV.

The kernel I landed on that is working now is:
4.4.0-116-generic