Grub2 - the switch

Postby **viking60** » 03 Aug 2012, 15:36

Well I have only just gotten used to Grub-legacy when it apparently is time to switch to Grub2. To avoid becoming a conservative grumpy Linux user I decided to replace my good ol' Grub with Grub2 on one of my Arch boxes. I thought I should share my nervous breakdowns with you guys:

So this is a long lived Arch 64bit installation that has behaved well on a Toshiba laptop. It looks like this when I boot into the LTS kernel:

So it is pretty much a matter of "simply" replacing Grub with Grub2. in my BIOS system.
Since I am very nervous at this point I chicken out and make a backup of my old grub stuff

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sudo mv /boot/grub /boot/grub-legacy

This is also handy for checking out what settings you had in the old menu.lst when you set up Grub2 later....

I also need to backup my current MBR which contains the boot code and the partition table

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dd if=/dev/sdX of=/path/to/backup/mbr_backup bs=512 count=1

Arch is also telling me:

Only 446 bytes of the MBR contain boot code, the next 64 contain the partition table. If you do not want to overwrite your partition table when restoring, it is strongly advised to backup only the MBR boot code:

So monkey see and monkey do:

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dd if=/dev/sdX of=/path/to/backup/bootcode_backup bs=446 count=1

This should be enough to save my bacon if I FUBAR :pray:

So here we go; time to replace the good old Grub (legacy) with the new Grub(2):
In Arch it is done like this:

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pacman -S grub-bios

So now the old grub is gone - probably not a good time to boot.....
Since I want to Install to 440-byte MBR boot code region
I setup grub-bios in the 440-byte Master Boot Record boot code region, populate the /boot/grub directory, generate the /boot/grub/i386-pc/core.img file, and embed it in the 31 KiB (minimum size - varies depending on partition alignment) post-MBR gap (MBR disks) or in BIOS Boot Partition (GPT disks):

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# modprobe dm-mod
# grub-install --target=i386-pc --recheck --debug /dev/sda
# mkdir -p /boot/grub/locale
# cp /usr/share/locale/en\@quot/LC_MESSAGES/grub.mo /boot/grub/locale/en.mo

Yes I only copied that code from the Arch site and the stuff monkey see and monkey do style.
That last command gave me an error message though ("not a directory"??) so by now I am sweating a lot. And no matter how often I repeat it the error stays so I feel I have no choice but moving on.Please Arch don't let me down now we are so close to the finish line..

Generating GRUB2 BIOS Config file to finish:

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grub-mkconfig -o /boot/grub/grub.cfg

/etc/grub.d/10_linux is set to automatically add menu items for Arch linux that work out of the box, to any generated configuration. Other operating systems may need to be added manually to /etc/grub.d/40_custom or /boot/grub/custom.cfg

Time to reboot then :pray:

Postby **viking60** » 03 Aug 2012, 17:23

Hey it worked!
Now the file that you will be editing the most is /etc/default/grub and every time you make changes you have to da a:

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grub-mkconfig -o /boot/grub/grub.cfg

That will generate the new grub.cfg for you. ( I do not know if this is Arch specific).

I see that Grub2 adds a lot of flexibility so I uncommented this line in /etc/default/grub:

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GRUB_THEME="/boot/grub/themes/starfield/theme.txt"

To have a sexy theme.
Then I put this background in /boot/themes/start/starfield and edited theme.txt to replace the default one.
Really nice!

bjoernvold.com

Grub2 - the switch

Grub2 - the switch

Re: Grub2 - the switch