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Hi I forget my GRUB boot loader password and cannot get into my Centos 6.3 OS. I read several ways on the web to reset the the regular password but ...
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  1. #1
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    GRUB boot loader


    Hi
    I forget my GRUB boot loader password and cannot get into my Centos 6.3 OS. I read several ways on the web to reset the the regular password but not how to clear the GRUB boot loader password. Any help. Thanks.

    Best regards

  2. #2
    Super Moderator Roxoff's Avatar
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    Boot up off an install disk (even a network install disk - these are a pretty light download if you don't have your original install media available) and select the repair option from the boot menu. Let the installer find your existing system, it'll normally make it available to you (i.e. it'll mount it) in '/mnt/system' or '/mnt/sysimage' or somewhere similar, and might require the root password.

    Once your existing Linux is mounted you can then use the 'chroot' command to make that the 'live' system. Then you can edit the grub configuration by hand and update the password, or remove it. You shouldn't need to re-install grub, but it shouldn't do any harm. When you restart your system you should be able to boot it in line with any changes you made.
    Linux user #126863 - see http://linuxcounter.net/

  3. #3
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    To reaffirm what Roxoff said, because invariable someone else may try to give you other information, boot from the INSTALL DISK. This will ensure you have all the necessary drivers and software to mount your existing system and chroot to it. Don't try to use a different distro's live cd.

  4. #4
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    Quote Originally Posted by mizzle View Post
    To reaffirm what Roxoff said, because invariable someone else may try to give you other information, boot from the INSTALL DISK. This will ensure you have all the necessary drivers and software to mount your existing system and chroot to it. Don't try to use a different distro's live cd.
    I 'm just going in circles. I cannot get anything to work.
    I was able to change the GRUB password with knoppin 6. However, at the GRUB menu, it just has option p so I chose it and get the grub prompt. All the other options after that gives me "Password for /dev/md0 (luks-0c0)" When I enter the GRUB password I get the the message "No key available with passphase.

    Any suggestion. thx

  5. #5
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    Remove the password from GRUB.

  6. #6
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    Quote Originally Posted by mizzle View Post
    Remove the password from GRUB.
    I was able to remove the password from GRUB only from knoppix.
    However, when I try to reset the login password since I forget that too, I always get "Password for /dev/md0 (luks-0C0...)" whether I use a or e from GRUB. I am not able to remove the password from knoppix because I cannot get to the file (shadow) even though I mount the root file system

    mount /dev/sda1 /mnt/sysimage and then cd /mnt/sysimage/etc for the shadow file. Thx.

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