LinuxQuestions.org - [SOLVED] Trying to install CentOS 7 and Windows 10 on same drive (dual boot)

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Trying to install CentOS 7 and Windows 10 on same drive (dual boot)

Hello:

I have a brand new ASUS VivoBook S15 (S530U). I installed Windows 10 on my SSD and then CentOS 7. After the CentOS install's final reboot, there isn't an entry in grub for my Windows 10 stuff.

Here's fdisk -l

Code:

disk /dev/sda: 1000.2 GB, 1000204886016 bytes, 1953525168 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 label type: gpt

Disk identifier: 873E25DD-2CDA-11E9-AD60-38BAF8FA5F68





#        Start          End    Size  Type            Name

 1        2048      1026047    500M  Microsoft basic 

 2      1026048    316117075  150.3G  Microsoft basic 

 3    316119040    316323839    100M  EFI System      

 4    316323840    317951999    795M  Windows recover 

 5    317968384    635920383  151.6G  Microsoft basic 

 6    635936768    953888767  151.6G  Microsoft basic 

 7    953905152  1052209151  46.9G  Microsoft basic 

 8  1052225536  1117761535  31.3G  Linux filesyste 

 9  1117777920  1150545919  15.6G  Linux filesyste 

10  1150562304  1183330303  15.6G  Linux filesyste 

11  1183346688  1216114687  15.6G  Linux filesyste 

12  1216131072  1248899071  15.6G  Linux filesyste 

13  1248915456  1281683455  15.6G  Linux filesyste 

14  1281699840  1380003839  46.9G  Linux swap      

15    317952000    317956095      2M  BIOS boot      

16  1697988608  1953509375  121.9G  Linux filesyste 

17  1380003840  1697988607  151.6G  Linux LVM      



Disk /dev/mapper/centos-root: 162.8 GB, 162806104064 bytes, 317980672 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

So I edited /etc/grub.d/40_custom like so:

Code:

#!/bin/sh

exec tail -n +3 $0

# This file provides an easy way to add custom menu entries.  Simply type the

# menu entries you want to add after this comment.  Be careful not to change

# the 'exec tail' line above.

menuentry "Windows 10" {

        set root(hd0,3)

        chainloader +1

        }

And then ran:

Code:

grub2-mkconfig --output=/boot/grub2/grub.cfg

When I rebooted, and selected the menu entry for "Windows 10", I got this:

Code:

Error: not an assignment invalid signature

I'm stuck, how can I get the Windows stuff in my grub so I can boot from either OS?

Any assistance you can provide is greatly appreciated!

I could be entirely wrong but I believe you need to run update-grub2

Take a look at the link below at the Opensuse site with info on Grub2. The command to update grub2 is below and needs to be run as root or sudo if used on opensuse:

Code:

grub2-mkconfig -o /boot/grub2/grub.cfg

The info in your first post shows an EFI partition. Are both CentOS and windows installed UEFI? You should see folders for Microsoft and whatever CentOS uses in the EFI partition if they are. The chainloader entry you used won't work on a windows EFI install. Try the below entry if you have the windows files on the EFI partition but running grub2-mkconfig should work. The set root line should point to your EFI partition (hd0,gpt3).

Quote:

menuentry 'Windows' {
insmod part_gpt
insmod fat
set root='hd0,gpt3'
chainloader /EFI/Microsoft/Boot/bootmgfw.efi
}

Quote:

Originally Posted by 1nuxg33k (Post 5960341)

I could be entirely wrong but I believe you need to run update-grub2

I get a command not found error.

[QUOTE=yancek;5960347]Take a look at the link below at the Opensuse site with info on Grub2. The command to update grub2 is below and needs to be run as root or sudo if used on opensuse:

Code:

grub2-mkconfig -o /boot/grub2/grub.cfg

I'm confused. That's what I wrote in my original post. Your command is the same as the one I ran.

Quote:

Originally Posted by yancek (Post 5960347)

This where I'm completely lost. I followed the ASUS instructions for booting from USB stick. Turning secure boot off and enabling "launch csm" (which also disables fast boot).

I have zero idea how to or not to specify UEFI.

I changed the BIOS settings, again secure boot and CSM, once, and only once and then installed Windows then Linux.

CSM mode is a BIOS emulation provided by EFI firmware - you should never use it IMHO.
I don't understand why you have so many Linux fielsystems - how many ties have you done the CentOS install ?. From CentOS go here and do as it says - post the RESULTS.txt so we can see what is what in that layout. While we're waiting for that, run these commands and post output

Code:

df -hT

sudo lsblk -f

[ -d /sys/firmware/efi ] && echo "EFI boot" || echo "Legacy boot"

Quote:

CSM mode is a BIOS emulation provided by EFI firmware - you should never use it IMHO.

Well... out of complete frustration and between your last reply, I wiped the disk, set CSM to disabled (ASUS lied), installed Windows, installed CentOS again.

Interestingly enough, the partition wizard had an option for /boot/efi as a mount point this time! That was NOT there with CSM enabled.

So I selected /boot/efi and when the install finished, I had both Windows and Linux in my boot menu!

Thanks for the help. By the way, I only had installed CentOS once. I have separate partitions for:

Code:

/var

/var/log

/var/log/audit

/var/tmp

/tmp

/boot <-- now /boot/efi

/swap

/home

/

Is there a way to mark things [SOLVED] in this forum?

Have a look in thread tools maybe - as OP you can mark it solved.
/boot/efi is not relevant to CSM/BIOS installs.