RAK3172. Error: Detect baudrate fail, can not get the baudrate on Arduino IDE

Hi, everyone!

I’m workig with a RAK3172 using de Arduino IDE. I tried to use a TSL2561 to read luminosity with this library. It Compiled ok, then uploaded it to my board but it didn’t work (Nothing comes to the Serial Monitor) then I tried to upload another program I knwo it work correctly (the RAK analog read example) but then i got this error:

Since then, I can’t no longer upload any code to my boards. This happend to 3 of my RAK3172. I tried to reset the board before upload but still the same.

Can you please tell me if there is any way to “erraese” this uploaded code from my rak3172 modules or anything I can do to repair them.

Thanks in advance!

Here is the code i uploaded

#include <Digital_Light_TSL2561.h>

void setup()
  // initialize serial communication at 115200 bits per second
  Serial.println("RAKwireless Light Sensor");

void loop()

  Serial.print("The Light value is: ");

Hi @ezroch ,

Can you try to send AT or AT+VER=? to see if your device is still responding to AT commands?

If you want a fresh start, you can always reupload the RUI3 firmware - RAK3172 Module Quick Start Guide | RAKwireless Documentation Center

Hi, @carlrowan

Thanks, for your quick response.

I tried to use the firmware upgrade tool, but I the serial port is not recognized by the tool or any other software i’ve tried

I also try with WisToolBox and it did not recognize

Can you please help me to recover these modules? :smiling_face_with_tear:

Hello @ezroch
When nothing works you can still try using ST-Link tool and download the hex firmware using STM32CubeProgrammer.

ST-Link connection

ST-Link hex firmware

1 Like


Where can I find all the hex firmware for RAK3172?


Nevemind, found it!


Hello @hunghp
Link to all firmware version:

Instructions to upgrade:

I have the same issue,
Before everything is good, I can upload my code.
But after someday, it still prints via Serial2 (string im uploaded before) but detects baud failure when im upload a new code.