Hi @dcaliste, I’ve finally updated to 4.4 and installed your patched version, and I’m happy to confirm that it works OK! Thank you once again, Damien!
Now I wish I could make it work faster so that calls are rejected quickly enough for the rintone not to start ringing for about one second… On 3G it is almost always sufficiently quick, but on 4G the 4G->3G switching seems to delay the hangup enough to make it start ringing before it gets hung up 
@dcaliste Would it be possible for you to recompile this patch for aarch64? I’d be extremely grateful…
Or, alternatively, could you please share the sources of this patched plugin and some short guide how to compile it? Thank you!
Here is the compiled version of ofono-ril-plugin with the patch.
To compile it, I did :
upgrade-4.4.0 branch : git clone https://github.com/mer-hybris/ofono-ril-plugin -b upgrade-4.4.0
sfdk) : mb2 -t <target name for 4.4.0 on aarch64, complete with TAB to get the name> -s rpm/ofono-ril-plugin.spec build
Actually, I don’t know if 10 iii is already using ofono-binder-plugin or not. The 10 ii is still using the legacy ofono-ril-plugin. Check with pkcon search ofono what is installed on your device. If it’s the new binder-plugin, I’ll have to compile it also. But it requires a bit of work since the upgrade-4.4.0 is actually requiring a more recent version of libgbinder-radio than the one available on 4.4.0…
Damien, thank you so much for compiling it! Oh, I haven’t thought about building it from within the virtual machine. I was only trying (and failing) to do it with sfdk. Thank you for the instructions, I will give it a try. I haven’t yet received that X10 III for tests, it is said to arrive by the end of the week. As soon as I have it, I will check if it is using the ofono-binder-plugin. If so, I understand that I should not install this ofono-ril-plugin?
Indeed, the patch should be applied on the installed package. If 10 iii appears to use the binder plugin, ping here, I’ll try to do it quickly.
Great, thank you. I’m still waiting for the delayed delivery, I will test it as soon as it arrives and I’ll confirm it here.
@dcaliste It turns out that I won’t get that X10 III for test, because in the meantime they got a client ready to buy it right away and they shamelessly sold it despite having promised to send it to me. Which is a pity because I really wanted to test it, especially that echo issue.
I am very sorry Damien for having taken your time to compile this, I will keep hunting for another opportunity to test it and as soon as I get it in my hands I will test the plugin and instantly report here.
No problem, my time is not that precious and @slava actually did all the work by providing a upgrade-4.4.0 branch ready to build.
Too bad you were not able to test the phone.
The 4.4.0.68 OS update now officially includes your patch and entirely solves the issue with rejected calls coming back and ringing again. Thank you @dcaliste so much for all your work!
Given how much faster the X10 III is compared to previous models, I was hoping that it would also finally be fast enough to be ablle to programmatically reject calls quickly enough for the ringtone not to start ringing before the call gets programmatically rejected. But sadly no, it does not differ compared to previous models and OS versions, i.e. once every couple of times there is still 1-2 seconds of ringing before the call gets rejected Enough to e.g. wake me up when I want to have some sleep (or if I am in a place where my phone should not be disturbing if not really necessary) and I use the call blocking app to only allow important calls through. Unfortunately, handling the D-Bus call is too slow to reject calls before they start ringing.
Does anyone know any way to speed it up?