How to remove windows (on/dev/sda3)

[Aravisian]

I do not recommend using Grub Customizer.

It makes decisions for the user, sets configurations in obscure locations and can be very difficult to untangle.

Instead, use efibootmgr as I outline in This Post:

Ubuntu install not recognzing windows 10 hard drive but gparted and fdisk recognizies

Yes, you can run with persistence to achieve this. I recommend Ventoy highly for this. It allows a bit more freedom in Persistent Distro Use. This sounds like information that is stored in the EFI partition, to me. This may be trickier, since Zorin OS will show up as Ubuntu in this field. An option may be to simply re-install Zorin OS as normal after removing all Ubuntu entries. Boot LiveUSB, then open a terminal and run efibootmgr This will list all boot entries in the EFI partition. It s…