UR22MKii: Using 5V DC port (cont.) SOLVED

edit:
Sorry, shortly after posting I figured out the correct procedure, so for future readers:

  1. connect interface via USB with power source set to Data USB
  2. when USB connection established connect external 5V supply
  3. then switch power source to external
    → Interface still working and getting power from external source.
    To verify pull external power source → interface turns of

=== original post ===
This is a follow-up/continuation of this thread (where it seems I can’t post a reply):
…/ur22mkii-using-the-5v-dc-port/670986 (sorry, can’t post actual links as I’m new here)

I have the exact same problem as the other posters there, connecting only an external 5V power supply (without having a computer USB connection) doesn’t turn on the interface.
I can tell this e.g. by switching on phantom power and the +48V LED doesn’t light up.

So can anyone confirm the 5V DC port actually works for supplying power and what we did possibly wrong?

Background:
I want to use the interface with my smartphone (USB host mode) which works, but want to prevent to draw the necessary power for the interface from the smartphone battery, hence external power supply.