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 bc0c7b0..4389934 100644
--- a/How-to-use-keyboard-UART-port-to-flash-firmware.md
+++ b/How-to-use-keyboard-UART-port-to-flash-firmware.md
@@ -10,6 +10,7 @@ here is the process:
 * put the switch 1 ON
 * connect uart with a **fpc 6p connector 0.5mm** to a serial-usb converter
 * use stm32flash to flash bin file
+* put the switch 1 OFF
 
 ## Whole connection view
 ![uconsole_kbd_stm32flash](https://github.com/user-attachments/assets/66a0028a-b6c1-4af2-92e7-91c6179fe272)