Is there any way of saving simple SMS mixed with MMS messages to an SD card prior to running a full factory reset? I got a Sony Z3 that refuses to send pic messages other than when I'm hooked to WiFi - Voda can't find or fix the issue and they suggest a full factory reset but I don't want to lose all the messages
I use SMS Backup & Restore, it works great! And it has a cloud plugin for saving messages to Google Drive and Dropbox.
Once installed, go to the app settings, and choose your SD card as backup folder.