Are you trying to delete 'nvram' file on the efi partition directly or are you trying to delete /sys/firmware/efi* ? I think it would be saver to use 'efibootmgr' instead of manually deleting 'efivar' or 'nvram' file.
Are you trying to delete 'nvram' file on the efi partition directly or are you trying to delete /sys/firmware/efi* ? I think it would be saver to use 'efibootmgr' instead of manually deleting 'efivar' or 'nvram' file.