RAK4631 Bootloader Update via Windows/USB successful but unit stuck in DFU mode (green led throb)

RAK4631 from WisBlock starter kit purchased Jan 2024

Followed Quick Start Guide for Windows USB installation and downloaded wiscore_rak4631_board_bootloader-0.4.3_s140_6.1.1.zip and adafruit-nrfutil.exe

executed the documented command (adjusting for updated zip file name and COM port for USB connection).

adafruit-nrfutil.exe --verbose dfu serial --package wiscore_rak4631_board_bootloader-0.4.3_s140_6.1.1.zip --port COM3 -b 115200 --singlebank --touch 120

Got the correct response from the device and it returned me to the command prompt as documented.

However, upon restarting the device by pressing the button, it remains with a GREEN led throb. I am unable to find it on bluetooth anymore. I’m understanding that this is DFU mode? How can I return it to normal functionality?


If the device is showing the green LED dimming on and off it is indeed in DFU mode. BLE is not active in that mode.
Is the device showing on your computer as an external drive RAK4631?

You can flash an application through USB either from ArduinoIDE or if you have a ready to use application in .UF2 format flash the application by dragging the .UF2 file to the external drive.

Thank you for the quick reply.

I do indeed have a RAK4631 drive in Windows 11 when double pushing the reset button on the WisBlock base board. I have found and copied the bootloader: wiscore_rak4631_board_bootloader-0.4.3_s140_6.1.1.uf2 to the drive. Which then makes the device quickly reboot.

However, after the instructions at the bottom of

The bootloader seems to be flashed but returns to DFU mode with green slow throb. I’m unable to see the device via bluetooth. I’m assuming after flashing the green led returns to its faster pulse-like state.

Current INFO_UF2.TXT
UF2 Bootloader 0.4.3
Model: WisBlock RAK4631 Board
Board-ID: WisBlock-RAK4631-Board
Date: May 20 2023
Ver: 0.4.3
SoftDevice: S140 6.1.1



I had a 2nd unit that I followed the procedure on, however this time I took the firmware from the meshtastic website and copied that to the RAK4631 drive that appeared in Windows. This time the firmware uploaded and rebooted the unit and returned to normal function and was discoverable and usable within the android meshtastic software.

The firmware used in this case: firmware-rak4631-2.2.17.dbac2b1.uf2

I followed the same procedure on my disfunctional unit and it did not work the first time but the 2nd time (and after removing the USB connection), was then discoverable and working again.

There is however, a problem with the bluetooth names coming up the same after the first unit is setup on the android device. The two RAK4631 WisBlock devices seem to want to have the same name in the bluetooth settings “Meshtastic_65df” despite being detected with a slightly altered name, the software keeps switching back.

I assume its not proper usage to have two WisBlock devices assigned to the same android phone device?

Regardless, I believe the hardware is functioning correctly. Thank you for your time.

Glad you could solve your problems.

For the identical ID of Meshtastic devices, I am afraid we cannot help. Meshtastic is not maintained or supported by us, we only sell compatible hardware. Maybe someone at Meshtastic.org can help.

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