[SOLVED] Reformat /boot

[Dr Small]

I have GRUB on a floppy all backed up, and I want to remove or reformat /boot so when the system boots, it will say there is no operating system, instead of taking me to a GRUB prompt.

What is the safest way to do this?

I plan to just open gParted and reformat /dev/sda1. Will that accomplish what I want to do ?

Dr Small

[meierfra.]

it will say there is no operating system,

Why?

Anyway, if you deleted the boot folder, or say just the grub folder, you will get a grub error (Probably Error 22)

"No operating system" would be a message from the bios. To get this you would have to delete the Grub code from the MBR. For example you could write zeroes to the first 440 bytes of the hard drive. (In this case it would not matter whether you still have your grub folder)

Some bios actually will report this error if none of your primary partitions have a boot flag. That can be easily achieved with "gparted" or "cfdisk".

[Dr Small]

Well here's the thing. I do have /boot/grub renamed to /boot/grub_bak, and it used to give me an error on Ubuntu, but now with it, it takes me to a grub prompt where I enter commands to boot it, rather that simply giving me an error.

[meierfra.]

Are you just try playing around to learning purposes? (I do that all the time)

it used to give me an error on Ubuntu, but now with it,

Did you change anything, which could have caused the different behavior?

it takes me to a grub prompt where I enter commands to boot it, rather that simply giving me an error.

This means that grub can still find the stage2 files, but cannot find menu.lst. Doesn't make much sense, since the stage2 files are also in /boot/grub. I had a similar experience once: I replace the stage2 file with the stage2 files from supergrub, but grub still used my old stage2 files. Only after reinstalling grub, the supergrub stage2 files were used. So I made up the theory that the grub code in the mbr contains the physical address for the stage2 files. So grub does not look for the file via the "/boot/grub/stage2" but goes right to the place on the hard drive, the stage2 files are stored. Renaming the grub folder does not change the physical location of the stage2 file. But I did same more experiment which seem to contradict this theory. So I'm not sure what really is going on.

[Dr Small]

Well, it certainly must be using Grub Stage 2 file somehow. I no longer have any 'grub' directory in /boot, as I moved it it my home folder, yet I am still taken to the 'grub>_' prompt at bootup.

So now the question, how would I go about reinstalling GRUB, so I can get this to work right?

I did this back on Ubuntu and never had a slightest problem. Just renamed 'grub' and then it gave me a GRUB File missing error. So I thought it should do similar on Arch. Apparently I have been proven wrong.

Yes, I am tinkering and playing around. Like to try different odd things at times that makes my friends look at me bewilderment

Basically, I like to have my system unbootable without the GRUB floppy. Sorta like an extra access key to get the system running, if you bypassed my BIOS bootup password

Dr Small

[MisfitI38]

Here's a reinstall guide for grub in the Arch wiki:
http://wiki.archlinux.org/index.php/Reinstalling_GRUB

[meierfra.]

Basically, I like to have my system unbootable without the GRUB floppy.

Writing zeros to the first 440 bytes of the hard drive and removing all boot flags will definitely do that. (But of course you could still boot your system with all kinds of external media other than a Grub floppy.)

I won't tell you how to write zeros to the MBR. If you can't figure that out by yourself, you shouldn't be doing it.

[Dr Small]

Ok. I found the command (or created it as I went, anyhow):

sudo dd if=/dev/zero of=/dev/sda1 bs=446 count=1

Didn't do squat, as I was still getting the same stuff after running it, so I reformatted sda1, and now I can't boot!!!!

Just kidding of course.
I moved all of the files in /boot over to /kernels and edited my menu.lst around to point to /kernels/vmlinuz sort of stuff, so now it works.

I then just flat out deleted sda1, resized sda2 and moved the remaining space into sda5, as my swap. Now when I reboot without the floppy in, I get:

GRUB _

(only the underscore blinks very fast )

I would have rather it not said GRUB, but I guess I can live with it. Thanks for all the help.

Dr Small

[meierfra.]

Didn't do squat,

That's because you are doing it wrong.

[Dr Small]

Thanks for the information. Maybe you could explain how I was doing it wrong, so I could learn from my mistakes?