I’ve finally terminated my upgrade to Xubuntu 11.10, with the usual small problems, nothing really too bad.
But now, when i boot I don’t see anymore the “Windows” entry in the boot menu made with grub2, I’ve installed os-prober that should help in will find additional entries on the hard disks and add them to the menu, but this don’t solved too my problem.
As alternative you could have your windows Entry in place, but when selecting it, you get an error like:
- you need to load kernel first
- chainloader: no such command.
- no such partition
Grub2 super short howto
This part comes from the complete tutorial about grub2 from the site Dedoimedo, while i was searching for an help i’ve read his complete how to about grub2 and i really suggest to take the time to read it for a complete overview.
GRUB 2 has three main parts:
- /etc/default/grub – the file containing GRUB 2 menu settings.
- /etc/grub.d/ – the directory containing GRUB 2 menu creating scripts.
- /boot/grub/grub.cfg – the GRUB 2 configuration file, not editable.
update-grub command reads the /etc/grub.d directory and looks for executable scripts inside it. The scripts are read, in the order of their numbering, and written into the grub.cfg file, along with the menu settings read from the /etc/default/grub file.
Boot entries come from several sources – the default that comes with the distribution, other operating systems probed on the connected disks and custom scripts written by the user, following a strict syntax. The scripts are written as shell (sh).
Step 1, know your hard disk
The first thing that you need to know it’s the exact mapping of your hard-disk, for this we’ll use the old but always good fdisk with the option -l, this is my Xubuntu machine harddisk
linuxaria@xubuntu-home:~$ sudo fdisk -l [sudo] password for linuxaria: Disk /dev/sda: 40.0 GB, 40007761920 bytes 255 heads, 63 sectors/track, 4864 cylinders, total 78140160 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xcccdcccd Device Boot Start End Blocks Id System /dev/sda1 * 63 36817199 18408568+ 7 HPFS/NTFS/exFAT /dev/sda2 36817200 42698879 2940840 c W95 FAT32 (LBA) /dev/sda3 42700798 78139391 17719297 5 Extended /dev/sda5 42700800 43698175 498688 82 Linux swap / Solaris /dev/sda6 43700224 59322367 7811072 83 Linux /dev/sda7 59324416 78139391 9407488 83 Linux |
So, in short :
/dev/sda1 = Windows
/dev/sda2 = extra partition formatted with fat32
/dev/sda5 = Linux swap
/dev/sda6 = / partition of Xubuntu
/dev/sda7 = /home partition of Xubuntu
My windows partition is /dev/sda1 that on Grub2 is mapped as (hd0.1), note that this is different from grub (not 2) where the first partition of the first disk was (hd0,0)
Step 2 create a custom Grub 2 script
Create the file /etc/grub.d/15_Windows, and add the following lines to it:
#! /bin/sh -e echo "Adding Windows" >&2 cat < < EOF menuentry "Windows" { set root=(hd0,1) chainloader +1 } EOF |
And now make this script executable with the command:
chmod +x /etc/grub.d/15_Windows |
Step 3 update grub 2 configuration file
Now, we must tell to grub 2 to recreate his config file, to do it execute, as root, the command update-grub2
root@xubuntu-home:/etc/grub.d# update-grub Generating grub.cfg ... Found linux image: /boot/vmlinuz-3.0.0-12-generic Found initrd image: /boot/initrd.img-3.0.0-12-generic Adding Windows Found memtest86+ image: /boot/memtest86+.bin done |
Now your custom script is included in the file /boot/grub/grub.cfg
You just have to reboot and enjoy (?) your Windows partition.
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nice; I’ve been adding it manually every update …
why not just run update-grub?
Done it, it doesn’t see my windows partition, otherwise it would be much easier
root@xubuntu-home:/etc/grub.d# ls00_header 05_debian_theme 10_linux 15_windows 20_linux_xen 20_memtest86+ 30_os-prober 40_custom 41_custom README
r
oot@xubuntu-home:/etc/grub.d# mv 15_windows /tmp/
root@xubuntu-home:/etc/grub.d# update-grub
Generating grub.cfg ...
Found linux image: /boot/vmlinuz-3.0.0-12-generic
Found initrd image: /boot/initrd.img-3.0.0-12-generic
Found memtest86+ image: /boot/memtest86+.bin
done
No windows entry with a simple update-grub.
There is something wrong in my Xubuntu 11.10 ?
It’s a fresh install with all the defaults.. so it took less time to add the windows entry manually than finding than problem.
Quicker way:
Boot the Live disc
Mount the Ubuntu partition: sudo mount /dev/sdaX /mnt
Run grub-install: sudo grub-install –root -directory=/mnt/ /dev/sda
Reboot, then run sudo update-grub
This gives you a newly installed grub2, which recognizes Windows
Thanks for the feedback Emery,
i tried that but it didn’t work, check my answer to the other comment.
Best Regards
I have always this f*#§ing error…
Generating grub.cfg …
Found linux image: /boot/vmlinuz-3.0.0-12-generic
Found initrd image: /boot/initrd.img-3.0.0-12-generic
Found memtest86+ image: /boot/memtest86+.bin
errore: syntax error.
errore: Incorrect command.
errore: syntax error.
error: line no: 98
Syntax errors are detected in generated GRUB config file.
Ensure that there are no errors in /etc/default/grub
and /etc/grub.d/* files or please file a bug report with
/boot/grub/grub.cfg.new file attached.
What is, by the way?
Hello,
Have you add something on grub.cfg on the directoy /etc/grub.d/ ?
It seem to be a syntax error somewhere.
just remove extra space between < <
cat << EOF
this worked for me
what is the script if my windows partition is in /dev/sda3 ??
(hd0,3) would seem logical for /dev/sda3
i mean the whole grub 2 script for my windows partition (dev/sda3). I am just curious about it.
Works for me, just be carefull with the spaces when you cut & paste the 15_Windows script from this page.
The shebang (# on the first line) should start the line without a space and the redirection >> should be two right angled brackets with no space in between.
Thanks for your script, it saved my day !
Quick remark for Fedora users : the “< <" characters give an error due to the space in between. "<<" is ok.
Also, don't use update-grub but grub2-install /dev/sda && grub2-mkconfig -o /boot/grub2/grub.cfg
@ Bill John : /dev/sda3 would be (hd0,3) in grub2.
Thank You….it really worked…as opoho said for fedora and centos users they have delete that space
does not work for me on CentOS 7.0. The command says succeeded but when I reboot I don’t see my windows 8.1 boot entry. Can someone please help.
Below is the output of my commands –
[root@localhost grub.d]# fdisk -l
Disk /dev/sda: 320.1 GB, 320072933376 bytes, 625142448 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk label type: dos
Disk identifier: 0xc6bb5f09
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 210419711 105208832 7 HPFS/NTFS/exFAT
/dev/sda2 210419712 413171711 101376000 7 HPFS/NTFS/exFAT
/dev/sda3 413171712 414195711 512000 83 Linux
/dev/sda4 414195712 625142447 105473368 5 Extended
/dev/sda5 414197760 625141759 105472000 8e Linux LVM
Disk /dev/mapper/centos-swap: 9437 MB, 9437184000 bytes, 18432000 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/mapper/centos-root: 98.6 GB, 98561949696 bytes, 192503808 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
[root@localhost grub.d]# grub2-install /dev/sda
Installing for i386-pc platform.
Installation finished. No error reported.
[root@localhost grub.d]# grub2-mkconfig -o /boot/grub2/grub.cfg
Generating grub configuration file …
Found linux image: /boot/vmlinuz-3.10.0-123.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-123.el7.x86_64.img
Warning: Please don’t use old title `CentOS Linux, with Linux 3.10.0-123.el7.x86_64′ for GRUB_DEFAULT, use `Advanced options for CentOS Linux>CentOS Linux, with Linux 3.10.0-123.el7.x86_64′ (for versions before 2.00) or `gnulinux-advanced-aaef1ef5-d9b1-4980-a624-470fd6b55f7c>gnulinux-3.10.0-123.el7.x86_64-advanced-aaef1ef5-d9b1-4980-a624-470fd6b55f7c’ (for 2.00 or later)
Found linux image: /boot/vmlinuz-0-rescue-7ab7bfde75e74d1099379d2f75695048
Found initrd image: /boot/initramfs-0-rescue-7ab7bfde75e74d1099379d2f75695048.img
Adding Windows
done
I think I am logged as admin, but I cannot save that script into /etc/grub.d/…