After playing with the config for Free mobile, some feedback:
- most of the received calls are on LTE, and mobile data is available during the call ; but sometimes, the phone switch back to 2G/3G for the incoming call. I didn’t find any pattern.
- sending SMS is not possible when VoLTE is registered. One needs to unregister and then SMS can be sent.
Playing with GitHub - fenrir-naru/mbn_utils: Utilities for Qualcomm mbn file to unpack mbn files, I indeed notice that /nv/item_files/modem/mmode/sms_domain_pref is set to use SMS over IMS (value 01), which doesn’t seem to be the prefered way for Free mobile. I tried to set it to 00 without success though : -( Ressources on the Internet on these tens of configuration options and values are quite few though… Some interesting links in case: