How to create a custom Grub entry?

My Windows 10 startup disk and partition is disk 1 and partition 3(ntfs). My bootmgfw.efi file is at C:\Windows\Boot\EFI.
How to create a custom entry?

I seem to remember disabling GrUB ability to detect other OS as a security measure earlier this year. I had to go into /etc/default/grub and change to this line:

GRUB_DISABLE_OS_PROBER=false

Then update GrUB, which then detect Windows partitions.

Not working

How ?

Provide Information:

It is not at all clear what you actually want to do.
Perhaps use a few more words.

If the issue is that your Windows installation is not picked up and integrated
then uncommenting this in /etc/default/grub :
GRUB_DISABLE_OS_PROBER=false
should do what you want.
(uncommenting means: remove the # in front of the line)
updating grub should then detect and integrate your windows installation so that you can choose it from the boot menu.
… which is (AFAIK) hidden by default
so: press ESC at boot to show it
or edit the file further to add a longer delay and/or unhide the menu

You had a (rather sparsely worded and therefore ambiguous) question.

as a response to an answer to that ill defined question is bordering on rudeness IMO

2 Likes

Just since it hasnt been mentioned …
Make sure to run

sudo update-grub

Not when OS Prober detects another OS.

good to know - I didn’t have the opportunity to experience, test or check that - because I don’t dual boot