Cannot operate Kodi without the remote…

I goofed when bringing my RPi Kodi media center back home from our vacation home….
Forgot to bring the remote control! It is a Motorola remote working through a USB Flirc interface and has worked fine for a long time.
Before that I used the Yatse Android app to control Kodi.

So I figured I could still use Yatse as a replacement remote until I could get the remote back home. But NOT!

Even though I updated Yatse to the latest version does it work.
It connects seemingly fine (no off-line error message once I entered the logon info into its settings).
But Kodi does not react at all when I try to use the navigation buttons, it does not even come out of the dimmed standby screen mode…

I managed to connect the web interface from my Win7 PC in another room and from there I could start playback of a video file on my network NAS.
With the video playing on the RPi screen it turns out that the Yatse remote app is able to pause, resume and stop the playing video file, but still it is not able to do anything else that I tested.

So what could be set up erroneously on this installation to block out the major parts of the Yatse interface?
Is there some filter file I need to modify in order to enable full operation of the Yatse commands?

System info:
Kodi runs on an RPi2 unit with OSMC as operating system. Updated about a month ago to the latest release.
It has a 1TB USB attached media drive with all the video (mp4) files on. This drive does not come up in the web interface when navigating the files path!
The remote (which is now not present) is a Motorola spare PVR IR remote connected via a FLIRC unit (USB).