@tekka Is there something I could help to spped up merging STM32duinoUpdate branch into master ? At the moment I have couple of blue pill boards (STM32F103C8) and want to test RS485 network with MySensors. And that I have one question, Is it possible to use two hardware serial ports - one for rs485 and another for debug prints ? What I tried is: using AltSoftSerial for rs485 but STM32 platform is not supported there using #define MY_RS485_HWSERIAL Serial1 and #define MY_DEBUGDEVICE Serial2 but Serial2 does not exist using SoftwareSerial but it seems that the code hangs somwhere and does not even get into setup() function (SoftwareSerial uses some timers so maybe they interferre with MySensors)