Update README.md

README.md

@@ -154,6 +154,7 @@ So this actually solves stability problems in **many** cases:
 
 When using ```SoftwareSerial``` (on Uno, Nano, etc), the speed **115200** may not work.  
 Try selecting **57600**, **38400**, or even lower - the one that works best for you.  
+In some cases **9600** is unstable, but using **38400** helps, etc.  
 Be sure to set correct TX/RX pins in the sketch. Please note that not every Arduino pin can serve as TX or RX pin.  
 **Read more about SoftSerial options and configuration [here](https://www.pjrc.com/teensy/td_libs_AltSoftSerial.html) and [here](https://www.arduino.cc/en/Reference/SoftwareSerial).**