Update fw_klipper.md

Author: 1coderookie

docs/firmware/fw_klipper.md

@@ -49,7 +49,7 @@ For further information about the installation steps please read the chapter ["I
 To build the correct firmware, use the following configuration during the setup process for creating the `klipper.bin` file:  
 
 - Micro-controller Architecture: Huada Semiconductor HC32F460
-- Communication interface: Serial PA03 & PA02 (Note: Serial PA15 & PA09 has been reported as well, but it seems that it didn't work at all boards and/or that one also would have to connect RST and GND at the mainboard to enter flash mode.)
+- Communication interface: Serial PA03 & PA02 (Note: Serial PA15 & PA09 has been reported as well, but it seems that it didn't work at all boards and/or that one also would have to connect the unpopulated RES and GND at the mainboard to enter flash mode.)
 - Application Address: 0x008000 (Note: or 0x100000 - not 100% sure yet, both seem to work.)  
 - Clock Speed: 168MHz (Note: 200MHz seems to work as well.)