How to restore grub in UEFI mode

Hi, I recently upgrade my debian (UEFI) and grub is gone.. I try to
recovery grub but failed or I`m doing something wrong.
This steps I following are:
-create usb with live cd
-change boot option to legacy mode and disable secure boot consequently
-boot from live cd (Here, when I boot from CD and check if i`m using EFI or
legacy, always say legacy, maybe be here the problem)
-mount my partition / in /mnt
-install grub in /mnt

when install grub i receive the following message:

> Installing for i386-pc platform.
> grub-install: warning: this GPT partition label contains no BIOS Boot
> Partition; embedding won't be possible.
> grub-install: warning: Embedding is not possible.  GRUB can only be
> installed in this setup by using blocklists.  However, blocklists are
> UNRELIABLE and their use is discouraged..
> grub-install: error: will not proceed with blocklists.
>

Can someone help me?