Weird behavior of UNO R4 Minima, even after flashing bootloader

Official Hardware Classic UNO R4 Minima
1

Hello everyone ! I recently bought an Arduino UNO R4 Minima. Everything went fine (program compiled and stuff) until the port stopped showing up in the Arduino IDE v2 on Linux Mint. I tried on Windows 10, and the result is the same.

Back on Linux Mint, I followed the instructions on this page to re-flash the bootloader using the Renesas cli tool (the port appeared this time as /dev/ttyACM0):

The program indicated that the flash was successful. However, even after changing the cable, the port is still not showing up in the Arduino IDE. When I enter the command lsusb, nothing happends (the command runs over and over and nothing shows up in console output) until I unplug the Arduino UNO R4 Minima and all the regular ports show up (without the R4 of course).

Back on Windows 10 again, when I plug the board to the computer, it displays this on a small window: "The last USB device you connected to this computer malfunctioned and Windows does not recognize it."

The board behavior when plugged in: only the green "on" LED is continuously lit. Nothing else.

I don't have the last program that ran on the R4 anymore but here is what I did in that program that compiled and was successfully uploaded to the board: I deleted the setup() function declaration to declare it in a main.S assembly file in which were the following code:

.global setup
setup:
    mov r0, #1
2

Hi @MnMsOre. Please try this experiment and then report back with the results:

  1. Connect your Arduino board to your computer with the USB cable.
  2. Press and release the reset button on your Arduino board quickly twice.
  3. If it is already open, close the Tools > Port menu in Arduino IDE.
  4. Open the Tools > Port menu in Arduino IDE.

Now please reply here on the forum thread with the answers to the following questions:

  • Do you now see the LED on the board pulsing?
  • Do you see a port for the board in the Tools > Port menu?
3

It worked, thank you for your help !

4

You are welcome. I'm glad it is working now.

Regards, Per