RAK4600 - Arduino Uploading failed

[Ded (Kris)]

When trying to upload Arduino code into the RAK4600 Evaluation Board, I am met with this error as shown below:

Repository Used:

RAKWireless/Evaluation_Boards

RAKWireless/RAK-nRF52-Arduino - BSP Installation

From the repos linked above, I understand that I have to download the appropriate packages/libraries for Arduino, flash the feather bootloader and then short RX1 and GND together and then press the reset button to get the EVB into DFU mode so that I can upload the Arduino codes. However, I am still unable to get the Arduino codes uploaded.

Some steps that I have undertaken are:
Deploying a virtual test environment on both windows and linux, but back to the same error.

Is there any other way for me to upload the codes? Thanks!

Some Notes:

Flashing of bootloader command:
pyocd flash -t nrf52 feather_nrf52832_bootloader.hex

Tools Used:
CH341 Serial Driver
CP210x_Windows_Driver

Hardware Used:
RAK4600 EVB
RAKDAP1
Jumper Wire (To short RX1 and GND)
Multi-meter (To test connectivity between RX1 and GND)

(I do not own a J-Link tool)

[beegee (Bernd Giesecke)]

Just to verify.
pyocd flash -t nrf52 feather_nrf52832_bootloader.hex
output was OK?

Any other application active that might use the COM port? Arduino Serial Monitor and Serial Plotter are closed? I had a bad experience with my 3D printer app Ultimaker Cura to block all Serial ports while running.

[Ded (Kris)]

The output seems fine.

As suggested, looking over at the device manager, I disconnected possible devices that could have been using the serial port. Serial plotter and Serial monitor was closed as well nor was I using the RAK serial port tool.

However, it is still unable to upload.

[beegee (Bernd Giesecke)]

Yes, the output of the the bootloader flashing looks ok.
I just repeated the steps on my RAK4600 EVB and when connecting RX1 to GND I can flash the module without any problems.

In ArduinoIDE when you open Tools->Port, is there only one COM port listed or several ports?

[Ded (Kris)]

Looking at both the ArduinoIDE and device manager, it shows 1 serial port being used which is the RAK4600 EVB.

Here is a picture of the board connection just in case. (Brass stand was used just for easier picture taking)

Is there possibly a different way to boot into DFU mode?

[beegee (Bernd Giesecke)]

There is unfortunately no other way to put the device into DFU mode.

The only thing I can recommend is to flash the original firmware again. Check if the EVB gives any output.
Then retry to flash the Arduino Bootloader.

[Ded (Kris)]

By output do you mean as such?

What if there’s no output?

[beegee (Bernd Giesecke)]

If there is no output at all on the Serial port, you should first try to flash the original RAK AT-Command firmware with DAPLink as shown in the documentation.

After successful flashing the AT-command firmware check again with the Serial tool for any output.

Once it is clear that the RAK4600EVB is working try again to flash the Arduino bootloader.