Ok, I'm in front of a computer now.
I'm not sure what cosv. A quick google says its comodore?
The 3 important files here are
10_linux
30_os-prober
40_custom
So, the update-grub command uses 10_linux to list any linux distros.
then, it uses 30_os-prober to find anything else (windows, bsd, other)
last, it copies anything in 40_custom (which is blank by default)
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The easiest thing to do in a dual boot (linux/win) system is to rename 30_os-prober to 09_os-prober
then windows will be first on the list.
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since you have a triple boot and want specific ordering, I would make a custom grub entry like this:
(do all this with a root file manager)
1. open the file /boot/grub/grub.cfg (this is the file that has your menu entries generated by update-grub)
2. go to the bottom of the file and find the menu entry for windows. It should look something like this
menuentry "Windows 7" {
insmod ntfs
search --set=root --label WINDOWS_7 --hint hd0,msdos2
ntldr /bootmgr
}
copy all 5 lines from "menuentry" all the way down to the "}"
3. now open /etc/grub.d/40_custom
paste the five lines for windows in here.
also find the five lines for the COS operating system and copy them in here
It should look something like this
4. Here is a good importunity to give your other os's a custom name.
find the line :
menuentry "Windows 7 loader on sdaXXXX" {
and change anything within the quotes to whatever you want
save the file
5. in the folder /etc/grub.d right click on the file 30_os-prober and select properties
go to the permissions tab and un-check the box "allow executing file as program"
this will stop update-grub from looking for other os's, but that's ok since you have them in 40_custom
6. now open a terminal and run the command "sudo update-grub"
done
7. **IMPORTANT** before you reboot, check the file /boot/grub/grub.cfg
you should see all your os's listed in the right order (down at the bottom)
linux, then windows, then COS
If you don't see the os's listed, check your work and don't reboot until this file looks right
kind of like this
https://docs.google.com/document/d/1YdO ... QXGcw/edit
After doing all this, your linux entry will still update when you get new kernels, whilst the other os's will just get added on.
I hope this all makes sense,