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Need to edit Ubuntu Linux boot parameters

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18 replies

by Jay Garmon 1 view

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I rushed foolishly into a full install of Ubuntu Linux on my COmpaq Armada M300 laptop. Now I've backed myself into a usability corner. Techncially, the OS is installed, I just can't really use it, because of the end-run I did around a video-driver catch-22.

Long story short, if I don't pass the boot parameter vga=771, I can't complete the install, because the native video driver goes wonky without the parameter. I need it to complete all the text-based config menus during the install. However, after the install process, the correct video driver is in use, and the vga=771 parameter causes the GUI interface to be unreadable. Luckily, I can drop to a terminal with [CTRL][ALT][F1], which gets me to a command prompt. My problem now is that I need to find out where the vga=771 boot parameter is specified and take it out of the boot process--all from the command line.

Unfortunately, I'm a total n00b, so I have no idea how to accomplish this. If somebody can point to where the boot parameters are specified and tell me how to edit them, I would be quite grateful.

18 replies

by jaqui

in the /boot directory you find the grub* configuration files.
the one you need to edit is most likely labelled default.

I use lilo so I am not completely familiar with grub. [ ubuntu uses grub by default ]

try passing init 1, as this is minimal services loaded, or else boot into the live version from the cd and mount the / partition from the hard drive, you will have to use a different name for it than / as there can only be one / mounted, and there is one mounted in the live version.

to mount:

mount /dev/hda1 [ if / is first partition, most likely ] /home/$user/temp

to edit the boot files you will need to use su, as they are owned by the root user.

*grub = GRand Unified Bootloader

by Jay Garmon

See my above comments. I'm inching closer (thanks for the grub hint) but not quite there yet.

by Jay Garmon

I've found a partial solution. I can hit ESC during the boot process and get to a GRUB editor, which will let me remove the vga=771 parameter for the current boot. This gets me into a healthy GUI session. The problem is that I have to do this for every boot, because the change isn't permanent.

I can get to the boot folder through the GUI, but I don't know which of the files to modiy, or what to change. My options are:

abi-2.6.12-10-386 (text file)
config-2.6.12-10-386 (text file)
initrd.img-2.6.10-12-386 (gzip file)
System.map-2.6.12-10-286 (test file)
vmlinuz-2.6.12-100386 (unknown file type)

Any clues?

by Jay Garmon

OK, I perused the local help file and found what I was looking for (I was way off track). The file I need to modify is /boot/grub/menu.lst. The problem is that this is a Read-Only file, at least from the GUI. I can clearly see where the parameter is specified, but I'm not sure how to change file permissions from within the GUI.

I suspect I can't, since the GUI is set to my user permissions, and I'm betting I can't either give my GUI session superuser access or switch to a GUI session under root. If I'm wrong on either count, I'd love to know.

If I'm not, I can easily drop to a terminal and do this from the command line, but I'm not entirely certain how to give myself superuser permissions from the command line, or switch to root. Any help would be appreciated.

by jaqui

yup,
that's where console comes in.
you have to use su to edit system files.
su = switch user

usage:
su[$user] default is root, so by not putting a user in you get the password prompt for root password

then, since it's always installed
vi [options] file
since the defaults will usually be fine all you need to enter is
vi [file]

make the change [ learning vi isn't easy ]
save the file
reboot

by jaqui

off to try ubuntu install on my system again, if it works I'll see what tools they actually have available in the gui.

by jaqui

msimko,
pico, joe, and emacs don't get installed by default.
the only default editor in every linux dostro is vim

which, as a text processor, is far to complex to be a default text editor, it has features and complexity that the default text editor shouldn't have.

by Jay Garmon

This was very helpful, except for vi, which I found hard (AKA impossible) to use. Luckily, Ubuntu does come with pico, which has handy on-screen commands.

by msimko

Open up a terminal from within the gui.

use 'su' to change to root. You'll have to give the root password.

Navigate to the menu.lst file. It is usually in the /boot/grub directory. You can use 'cd' to change directories.

edit the menu.lst file as you need. to edit it, you can use vi, emacs, or pico.

You can get instructions on any command by using man. example: 'man vi'. Press 'q' to get out of the man help file. Vi can be tricky. Maybe best as a nubie to use pico.

Good luck.

by Jay Garmon

Pico was just the editor I needed. Unfortunately, the only way I could obtain root access was by booting into recovery mode. I had to combo this advice with some other workarounds. See my comments above.

by craiglarry9

wipe your hard drive put on winxp and download vmware with brower-appliance and run ubuntu 5.10 in virtual, no muss no fuss

by craiglarry9

wipe your hard drive put on winxp and download vmware with brower-appliance and run ubuntu 5.10 in virtual, no muss no fuss

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