diff --git a/How-to-use-keyboard-UART-port-to-flash-firmware.md b/How-to-use-keyboard-UART-port-to-flash-firmware.md
index e6cba85..ba4b9cf 100644
--- a/How-to-use-keyboard-UART-port-to-flash-firmware.md
+++ b/How-to-use-keyboard-UART-port-to-flash-firmware.md
@@ -5,7 +5,7 @@ Especially at when your keyboard met problem
 here is the process:  
 
 * put the switch 1 ON
-* connect uart with a fpc 6p connector to a serial-usb converter
+* connect uart with a **fpc 6p connector 0.5mm** to a serial-usb converter
 * use stm32flash to flash bin file
 
 ## Whole connection view