We are using the XBee3 LTEM/NB-IoT modem (u-blox SARA-R410M-02B-01 cellular module), configured for 115200 baud and API operating mode. We run our own 32-bit processor behind the Digi modem, using XBee ANSI C library written by Tom Collins.
We observed that sometimes the modem would lose its configured profile as if a factory reset had occurred, i.e., reversing itself back to 9600 baud and Transparent mode. There is no code in our firmware to issue a factory reset command. I am wondering if there is a hidden, undocumented I/O pin toggling feature that we might have accidentally stumbled upon that would reset a modem to its factory default. Otherwise I can’t find an explanation for this.