dual boot

pan64 · 04-30-2019, 08:08 AM

That is an interesting question (at least for me).
I have an ubuntu and a debian installed (and also a win10 and win7). Now the boot loader is installed from ubuntu, therefore if I modify debian (kernel) the boot loader should be updated from ubuntu (if I knew it well).
How can I configure my system so update-grub2 works the same way from debian and ubuntu (=will generate exactly the same grub menu/config).

colorpurple21859 · 04-30-2019, 09:17 AM

What I do is create a /etc/grub.d/25_custom with the following in Ubuntu and run sudo update-grub.
This puts the menu entry before the os-prober entries.

menuentry "Debian"{
set root=(hd0,2) #change accordingly for your Debian install
configfile /boot/grub/grub.cfg
}

That way I don't have to remember to go back to ubuntu to run update-grub when changes are made in Debian due to updates or anything else, just run update-grub in Debian.

mrmazda · 04-30-2019, 10:03 PM

http://fm.no-ip.com/Share/Linux/custom.cfg is an example subset of what I do on UEFI systems (which have 6 or more Linux installations). It works much like what colorpurple21859 does, except this file is /boot/grub/custom.cfg, and instead of /etc/grub.d/25_custom, I rename 40_custom to 06_custom, without making any changes to the file's content. This also puts my (much less elaborate) custom entries at the top of the boot menu.

BW-userx · 05-01-2019, 09:35 AM

Quote:

Originally Posted by colorpurple21859

What I do is create a /etc/grub.d/25_custom with the following in Ubuntu and run sudo update-grub.
This puts the menu entry before the os-prober entries.

menuentry "Debian"{
set root=(hd0,2) #change accordingly for your Debian install
configfile /boot/grub/grub.cfg
}

That way I don't have to remember to go back to ubuntu to run update-grub when changes are made in Debian due to updates or anything else, just run update-grub in Debian.

I am trying this little "trick" and it not working yo.

Code:

menuentry "Void Linux" {
set root='(hd1,7)'
configfile /boot/grub/grub.cfg
}

errors out.

Code:

$ sudo update-grub
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-huge-4.19.37
Found linux image: /boot/vmlinuz-huge
Found linux image: /boot/vmlinuz-generic-4.19.37
Found linux image: /boot/vmlinuz-generic
/etc/grub.d/25_custom: line 1: menuentry: command not found
/etc/grub.d/25_custom: line 3: configfile: command not found
/etc/grub.d/25_custom: line 4: syntax error near unexpected token `}'
/etc/grub.d/25_custom: line 4: `}'

as the other files have a x attached to them and it was not picked up I added one to the 25_custom and now am getting them errors. now what?

should that be in 40_custom instead?

and it is on the second hdd and 7th partition, so should it be counting from 0 to 7 making it hd1,6 or keep it 7?

colorpurple21859 · 05-01-2019, 10:35 AM

I think I copied 40_custom to 25_custom and added entries. I'll have to wait till I get home from work to check.
grub2 counts drives starting at 0 and partitions starting at 1

BW-userx · 05-01-2019, 10:38 AM

thanks, that little bit in the top of 40 might be the why my 25 is not taking.