Old Mac dfu

DFU mode is only available on 2018+ USB-C Macs.

If you want to reinstall macOS on an older Mac, then you can either use Internet Recovery Mode (Command + Option + R), or by creating & using a bootable macOS USB installer.

Edit: I forgot that an iMac Pro had DFU Mode as well.

DeezNutskid wrote:

how to put an old Mac (Mac mid 2014) into DFU mode \

Revive or restore an Intel-based Mac using Apple Configurator - Apple Support