[Solved] Configuration of LG MAGIC MR21GA remote control with ULTRABOX+ decoder and LG soundbar

Hello.
I have been using an LG 65nano853pa TV with LG soundbar and Ultrabox 4k decoder from Canal for a few weeks now. The TV has a Magic MR21GA remote control. After a power outage, or disconnecting the decoder and reconnecting, the TV reconfigures the remote as universal to the decoder. The problem is that after auto-configuration, the remote cannot be used to control the decoder; you cannot switch channels etc. On top of this, the soundbar is muted.

I go into the settings of the universal remote, delete the settings and try to configure from scratch. The configurator allows you to select the type of device: DECODER, the service provider automatically suggests CANAL, I click NEXT and a board informs me that a test for correct interaction should be performed. I click NEXT, the board "Select the button below and check that it works correctly on the TV screen on the right" appears, then immediately disappears, without displaying these test buttons, and goes automatically to a summary that the configuration has been completed. But it still doesn't work properly.

Does anyone know how to "force" these test buttons to appear, so that you can decide for yourself which settings to choose?

I don't know if this helps, but when you test and try to change channels, do you aim the remote at the decoder?
I say this because at first I thought the decoder was controlled by the radio link via the TV but the magic remote also has an irda (infrared) transmitter and it is with this that it transmits the signal to the controlled decoder.
So the volume up and TV functions work everywhere (radio link) and the decoder functions as with a traditional remote control.

I have exactly the same problem, the difference is a remote control, an MR21GC, and a set-top box from multimedia, and no matter how I point the remote control, the effect, the same, it does not connect, all the functions of the TV work, but the set-top box does not respond to anything at all despite the fact that I have done the configuration of the remote control and the set-top box several times

Well, but in order to complete the configuration of the remote control, the remote control has to change the channel on the decoder during configuration. Does it then work properly during setup?
By the way...they ate this new remote control, it has no Play and Pause button.

You mean this test during setup? No, no reaction from the decoder, neither forward nor backward channel nor anything else

Check if the decoder is connected via HDMI ARC input, if so, try, select the decoder manually during configuration and check if this decoder has the possibility of configuration at all. I have an EVOBOX decoder and the configuration goes through successfully.

Only now yes, the configuration is manual from a to z, I select everything myself, still nothing. I would just like to add that before, during the first configuration, everything worked without the slightest problem, today I unplugged the hdmi plug and suddenly there were circuses

As I wrote earlier. Have you plugged in the HDMI ARC input?

Yes, it is plugged in

Well, I don't know anymore. I would still try unplugging everything from the power supply, plugging it in again and probably by trial and error combining. Restore the decoder to factory settings and even before that I would try on a different HDMI cable, that's also how it can happen that the cable is doing the problem.

@gadek80 What does ARC have to do with it????
https://rms.pl/baza-wiedzy/3316-hdmi-arc-i-earc-co-to-jest-i-do-czego-sluzy
@Sztejkowy In tv settings - HDMI-CEC, HDMI-SYNC, control via HDMI have you checked?

I have not looked here for a long time. With me, the problem has not occurred for some time now. High probability that they have solved it with a software update

you can try entering the decoder menu/decoder/TV control (CEC) and enable YES

Updates to the set-top box and TV software have introduced a solution to the problem