LinuxQuestions.org - How to uninstall grub from my usb??

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linus72

04-14-2009 06:41 PM

How to uninstall grub from my usb??

Did an hd install of dsl to my USB, now having permission/boot problems after trying to remove Grub.
How do I get Grub completely off the usb?
Do I have to dd the MBR?
How?
Thanks

Mr-Bisquit

04-14-2009 06:49 PM

Did you follow the instructions for a persistent image?

http://www.knoppix.net/forum/viewtopic.php?t=23558

Whatever your main OS version is, use the first disc to do a rescue then just use the BIOS boot selection to use the usb key when necessary.

linus72

04-14-2009 07:14 PM

I asked how to get grub off my usb-not put Knoppix on my usb-
So-how do I get Grub off my USB?
Do I use the dd command? "dd if=/dev/zero of=/dev/sdf1"??

hurry_hui

04-14-2009 08:44 PM

I think you need to include block size, bs=512 to remove partition table and bs=446 to remove only MBR. It then like dd if=/dev/zero of=/dev/sdf1 bs=446 count=1. I am not so sure. Someone might correct this.

linus72

04-15-2009 06:26 AM

OK-that didn't work either-
So far I've deleted/formatted the USB and did dd if=/dev/zero of=/dev/sdf1 bs=446 count 1
I also tried /dev/sdf and /dev/null.
Nothing works-when I try to boot off the USB grub is still there!
So-how do I get Grub off my usb mbr?

jolphil

04-15-2009 06:57 AM

Hello,
I have always relied on Ranish Part image for those pesky hard to get rid of partitions..I do not know if it will work on USB though..Maybe someone else has used it there can respond..
Thats all i can think of now..
Goodluck,
jolphil

Edit Later: I just did a test on two of my computers(one older and one newer) and Ranish did not see the USB drive..Thus I am sorry It does not seem to work here..

linus72

04-15-2009 08:08 AM

So does anyone know why I can't remove grub from my usb mbr?
I have tried almost everything and it's still there-??

repo	04-15-2009 10:39 AM

Quote:

dd if=/dev/zero of=/dev/xxx bs=446 count=1

is the correct syntax.

Code:

bs=446 => removes MBR

bs=512 => removes the partition table

What is the device from your USB ?
what is the output from

Code:

fdisk -l

linus72

04-15-2009 11:32 AM

I did all that Repo-
I still get a grub prompt at boot with a flashing ">"
I even installed syslinux and nothing-re-formatted.
I'm at a loss here....

repo	04-15-2009 11:40 AM

Can you please give the command and the output you get when you execute it?

Code:

dd if=/dev/zero of=/dev/sdf bs=512 count 1

Also what is the output from fdisk -l with the usb connected.

linus72

04-15-2009 11:48 AM

Output of fdisk -l

Code:

root@bz-desktop:/home/bz# fdisk -l



Disk /dev/sdf: 4045 MB, 4045930496 bytes

255 heads, 63 sectors/track, 491 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Disk identifier: 0x0006a054



  Device Boot      Start        End      Blocks  Id  System

/dev/sdf1  *          1        491    3943926    b  W95 FAT32

output of dd-

Code:

root@bz-desktop:/home/bz# dd if=/dev/zero of=/dev/sdf bs=512 count=1

1+0 records in

1+0 records out

512 bytes (512 B) copied, 0.00724268 s, 70.7 kB/s

Now, again I'll try and see if it will boot with no grub ">".

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