Question How does GRUB and UEFI boot work?

Jun 10, 2019
I installed win10 and a Linux for dual boot on the same ssd, during the installation of Linux, it contains a grub. After installation, I can see there is a new Linux efi file added to the ESP partition. Now I decided to remove the Linux entirely, the first step I did is to remove the efi boot entry with a tool called EasyUEFI. The entry disappeared when I reboot and pressing F11.

But there are 2 parts confused me:

  • The Linux efi file is still in the ESP partition after the entry is removed, I thought existence of such efi files are how the UEFI would know if there is such boot option when user press F11 when booting. Now this means the boot options is recorded somewhere else, and the EasyUEFI tool simply removed that. Where is it, is it in ESP partition?
  • I am not quite sure if I understand this right, are UEFI boot (the efi file and whatever other boot records it added during installation) and grub the same thing now? Or it’s when user select an efi boot entry, it goes to grub boot menu, which is a separate thing? If efi boot can handle the boot selection already, isn’t it pointless to have a grub after?
Thank you!