Hello again!
I've tried adding manually to submodules/linphone/coreapi/linphonecore.c a different payload type (in particular payload_type_h264 with profile-level-id=4D0029), but when the call is accepted, I still get the following error:
10-12 12:38:03.283 29515-29678/com.be_ssd.sipinterphone I/SIPManager: Found payload H264/90000 fmtp=profile-level-id=4D0029; packetization-mode=1
10-12 12:38:03.293 29515-29678/com.be_ssd.sipinterphone I/SIPManager: No match for H264/90000
I've built the library with BUILD_X264=1, but still I only see that only msopenh264-android plugin is being registered (and not msx264)...