This contains the command line version to update:
Refer: http://www.linuxandubuntu.com/home/how-to-change-boot-order-set-default-boot-os-in-ubuntu-14-10-15-04-linux-mint-or-other-derivatives
How to set Windows 10 as default in Ubuntu (grub) boot loader with GUI
Refer: https://www.itsupportguides.com/knowledge-base/ubuntu/set-windows-10-default-ubuntu-grub-boot-loader/
The following steps show how to set Windows 10 as the default operating system when using the Ubuntu (grub) boot loader.
This is for when you are dual-booting Windows 10 and Ubuntu.
We’ll be using the Grub Customizer software by Daniel Richter.
Step 1: Install the Grub Customizer software
If you haven’t already, boot into Ubuntu
Click on the Ubuntu icon in the launcher to open the search dialog
Type “terminal” and click on the icon when it appears
In the terminal – run the following command
sudo add-apt-repository ppa:danielrichter2007/grub-customizer
Enter your password
Press ‘Enter’ on your keyboard when prompted
Now run the following command
sudo apt-get update
When it’s done, run the following command and enter ‘Y’ when prompted
sudo apt-get install grub-customizer
Step 2: Change the boot order
Click on the Ubuntu icon in the launcher to open the search dialog
Type “Grub” and click on the Grub Customizer icon when it appears
Enter your password in the prompt and click ‘Authenticate’
In the list you will see the item for your Windows 10 installation. Click on it.
Now use the arrows in the toolbar to move it to the top of the list.
Click ‘Save’
Now restart your computer and confirm that Windows 10 is now the default boot option.