Ubuntu Boot to Blank Screen with Blinking Underscore (Cursor)

Today I was installing the Ubuntu 14.04.02 LTS into a server using a USB thumbdrive. Everything went smooth, as usual the setup asked to remove the USB thumbdrive before continue to Reboot.

After reboot, it hangs on a black screen with blinking underscore / cursor. Waited for 15 mins, nothing happen. If you encounter the same error like I do, it is possibly caused by:

1. a corrupted GRUB
2. the setup simply installed the GRUB onto the USB thumbdrive accidentally. (I suspect it is because I have chosen to umount the thumbdrive during the setup)
3. graphics driver not supported (it sounds a bit weird to me, if the setup could run well in GUI, why should a reboot not?)

For the first two reasons, a simple solution is to repair the GRUB. Here's the complete guide for Ubuntu users. For my case, because I knew the GRUB is in the thumbdrive, so I simply plug it in and choose my HDD as first boot device, it then boot into Ubuntu successfully, then I run the following command in terminal:

sudo add-apt-repository ppa:yannubuntu/boot-repair
sudo apt-get update
sudo apt-get install -y boot-repair && boot-repair

and then follow what is being instructed by the boot-repair. The only steps that caused a confusion is which disk or partition to select as GRUB install location. A rule of thumbs is don't select the partition, select the disk.

For 3rd reason - graphics driver broken. I personally do not try it, but someone from online said it can be fix by inserting the -nomodeset in between ro quiet splash. And I do believe you realize one thing now... if you could see the GRUB and able to insert the -nomodeset, well, then it is most likely your problem is more challenging, good luck hunting it down!

[Fedora] Omit GUI and boot with or into command line

Before you start, you need to know what is runlevel.

runlevel is a number that indicates which mode the computer to boot into. For instance, runlevel 5 is graphical mode, where runlevel 3 is text-only mode. Runlevel 1 is single-user mode, commonly used for troubleshooting.

And GRUB (GRand Unified Bootloader), a bootloader which allow you to choose which OS to boot into during computer start up. Here's a screenshot of GRUB.

Now, there are two options:

1. boot with command line, means omit the filling up Fedora logo and show the boot progress by command line
2. boot into command line, means completely omit booting into GUI and end up in command line

What you need to do is at the GRUB screen, select your Fedora OS name and press "e".
Then find rhgb in the line start with linuxefi /vmlinuz. On the right side of rhgb should be word "quiet".

For option 1: Remove the rhgb from the line and press CTRL+X or F10. This should show the command lines as boot progress instead of the Fedora logo. Useful for identifying what has failed during boot progress. The system will still end up in GUI afterwards.

Sample = ... rhgb quiet ... 

For option 2: Here's why you have to understand the runlevel. You achieve this by simply add a runlevel number "3" after the word "quiet" (space in between two words) and press CTRL+X or F10. This should boot the system into CLI instead of GUI.

 Sample = ... rhgb quiet 3 ...

Note:

• rhgb = RedHat Graphical Boot

How to Fix Multi-boot - Lost of any OS installed before Ubuntu

Big thanks to Ryugamine Mikado from General Linux Discussion Malaysia for sharing such a nice option to fix the multi-boot!

@Tecsun Yeep hi there oh it actually scans the entire disk for all OS and it has been PROVEN to recover any type of OS (i myself used it once to recover my arch when I accidentally fuk'd up my grub.conf) plus many more options such as recovering partition tables , bootsectors and such but i think it only works with GRUB/GRUB2 ,so if you're using another type of bootloader such as LILO you would have to resort to something else

The GUI method of fixing the multi-boot - lost of any OS installed before Ubuntu is well documented here: https://help.ubuntu.com/community/Boot-Repair

Here's a screenshot of it:

How to Fix Multi-boot, Fedora Gone after Install Ubuntu

Updated 30 Jan 2013 11.25pm:
A much more user-friendly method with GUI. Click here to see how.

---

I was installing multi boot environment on my laptop, it will be consist of:

1. Windows 7 Pro
2. Fedora 18
3. Ubuntu 12.10

Fedora & Ubuntu both use Grub2 to multi boot, installing Fedora after Windows work fine, but once Ubuntu was installed only Windows 7 can be seen from the list, Fedora was gone. How do we fix that inside Ubuntu?

There are various fix on internet which can be concluded below:

1. update-grub: you might have to install grub first before you able to run this command
2. grub-customizer: this is very handy GUI to manipulate the Grub. It supports Grub2 and it is real intuitive to add new OS onto the Grub menu list.
3. manual configuration by typing entries: intermediate/advanced user might appreciate this but definitely not for novice user. There are too many things to learn before one can eventually get it run correctly.

The first two methods are the most straightforward method, but it might not work as expected sometimes. My version of getting this solve is pretty simple, despite it required to work with method no. 3.

* To edit grub.conf user is required to open Nautilus with sudo privilege. Make sure you have run sudo nautilus & in terminal to be able to open and edit the configuration file in text editor.

1. First thing you have to know where the Grub configuration file is stored. It is located under /boot/grub/grub.conf. Open it with a text editor.
2. Then you have to know where is your Fedora /boot located. We don't need terminal as we love GUI. Go to Dash Home > Disks.
3. If you follow Fedora installation guide you can easily identify the /boot, which is 25x MB in size. There are two in my Disks Manager, but the already mounted one is for Ubuntu. So the other one is Fedora for sure.
   
   
4. Mount the Fedora /boot by select the partition and press the play button. 
5. Open the /boot/grub2/grub.conf with text editor.
6.  Locate the following and COPY the whole content except for the ###BEGIN....### & ### END....###:

7.  ### BEGIN /etc/grub.d/10_linux ###  
    menuentry 'Fedora' --class fedora --class gnu-linux --class gnu --class os
   . 
   .
   . *this dots mean there are a lot of content in the middle but being skipped
   . for ease of reading purpose
         }  
    }  
    ### END /etc/grub.d/10_linux ###  

8. After that, switch to your Ubuntu's grub.conf, and paste into ### BEGIN /etc/grub.d/40_custom ###, see screenshot below:
   
   
9. Save the Ubuntu's grub.conf and reboot.

Voila! My Fedora 18 is now shown on the Grub boot menu.

Ubuntu starting in low graphics mode?

If you ever encountered Ubuntu starts in low graphics mode, it could be due to the following:

1. your "/" or "/boot" partition are full. Do a check with df -h, if it is the case then clean out some useless stuff and do a reboot
2. the lightdm or gdm is corrupted. Uninstall it completely with sudo apt-get purge gdm or sudo apt-get purge lightgdm, then reinstall with sudo apt-get install gdm. Select lightdm or gdm from the menu. (you might try lightdm first, if it still give problem, go with gdm)
3. the desktop might have corrupted. If you are using XFCE4 like I do, continue with sudo apt-get purge xubuntu-desktop and sudo apt-get install xubuntu-desktop. Same method work for ubuntu-desktop.