I’d really appreciate it, thanks!
In order to replicate my configuration you should connect the IO1 pin to pin 6; regarding the sensors they shouldn’t have anything to do with my problem and even if you don’t connect anything to the board the firmware should handle their absence by sending some special values.
I had to rename the files to fit the format restrictions imposed by the forum, obviously you’ll need to remove the final “.txt” 
Firmware_FeatherM0.ino.txt (9.1 KB) myHeader.h.txt (2.1 KB)