I just PR this fork supports using SDI-12 in the Boron LTE to the open-source EnviroDIY SDI12 library. You can try it from joaquinperaza/Arduino-SDI-12
I am using the ClimaVUE atmospheric sensor without any other board running smoothly. I just plugged into the D2 of the Boron and started receiving data. I also included a script for testing in the examples folder.