If your EFI based PC is not booting debian, here is an easy way to reinstall grub- efi, the bootloader used by debian on these PCs. Contents.
Reinstall the GRUB boot loader to your Ubuntu installation in EFI mode this way.. . Boot from the Ubuntu installation medium and select 'Try.
A GRUB/EFI examples article has been provided for such cases. The section assumes you are installing GRUB for x86_64 systems.
Note that in a UEFI-mode installation, Ubuntu will not ask you /boot/efi); it uses the grub-efi bootloader (not grub-pc).
This will fix on a standard installation, if you do manual partition, ask at the forum! Boot up with our LiveIso. mount System to /mnt. You need to.
dnf install grub2-efi shim yum install grub2-efi shim. If you do, then try: dnf reinstall grub2-efi shim yum reinstall.