Nano RP2040 Connect not showing as a device under ports

I just got the new Arduino Nano RP2040 Connect and already messed a bit with it, i.e. Blink sketch, serial interface, etc. and it all worked inside the Arduino IDE. Then I uploaded the RP2040 MicroPython UF2 from here and now neither the Arduino gets displayed as an USB device in Windows Explorer/macOS Finder nor inside the Arduino IDE under Ports. But I would like to use it again with the Arduino IDE. I can't upload anything anymore.

Tested on both Windows 10 and macOS Big Sur.

Is my boot loader messed up? If so how can I burn it again? I have a spare Arduino Uno if that would help.

Hi Benny! Holding the REC pin (you can find it reading the silk) to gnd (use a tweezer) and resetting the board you force the ROM bootloader. The device should show up as as RPI mass storage so you can flash on it again an Arduino uf2 and everything should be factory restored. Can you please try and be back to me?

P.S when the mass storage show up remove the tweezer!

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This is the factory blink you get with you board!


Thanks for the quick response! I'm trying it now

Sorry where can I find the REC pin?

it's the pin close to GND and VIN below the arduino logo... see picture
the pin is conventiently located beside gnd so you can short it easily

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Ahh found it. Okay I connected both pins using the tweezer and pressed the reset button. But nothing happened. Do I have to plug it in with both pressing the button and connecting REC to GND?

Aha okay tried it again on Windows. Got the Arduino mounted

OMG it works again!!! Thank you so much! I think it would be awesome to have this in FAQ.

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Okay now every time I upload the Arduino disconnects and re-connects, according to the Windows connect and disconnect sounds and Windows Explorer popping up, showing the RPI-RP2 device folder. The upload works nonetheless.

Did you remove the Short circuit after the mass storage shows up?

The same here, (IDE 2.0 but still the same on IDE 1.8.xx) when i try to send the sketch to my nano 2040 connect i obtain this:
Sketch uses 78840 bytes (0%) of program storage space. Maximum is 16777216 bytes.

Compilation complete.
Upload error: Error: 2 UNKNOWN: uploading error: uploading error: exit status 1
It open the 2040 folder but it don't send the code to the board.

seems i have resolved pretty all after reading this:
New Arduino cores for Pico and Nano RP2040 Connect! - #5 by alranel

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You mean REC to GND? Yes I did that.

I get this sometimes as well. What I do then is to double click the RESET button which should open up the RP2040/RPI-PI2 folder (and thus hopefully re-connect the Arduino) and then try to upload the sketch again. This assumes you got the fix (i.e. REC to GND with RESET button pressed) working.

would you please also share the code of the factory blink?
I'm totally new to this and would like to have a look at the code also.
Thank you in advance!


#include <WiFiNINA.h>

void setup() {
  pinMode(LEDG, OUTPUT);
  pinMode(LEDB, OUTPUT);
  pinMode(LEDR, OUTPUT);

int ledState = LOW;
int rgb = 0;

unsigned long previousMillis = 0, interval = 1000;

void loop() {
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;

    rgb += 1;
    if (rgb == 3) {
      rgb = 0;

    if (ledState == LOW) {
      ledState = HIGH;
    } else {
      ledState = LOW;

  digitalWrite(LED_BUILTIN, ledState);

  switch (rgb) {
      digitalWrite(LEDR, LOW);
      digitalWrite(LEDG, HIGH);
      digitalWrite(LEDB, HIGH);
    case 1:
      digitalWrite(LEDR, HIGH);
      digitalWrite(LEDG, LOW);
      digitalWrite(LEDB, HIGH);

    case 2:
      digitalWrite(LEDR, HIGH);
      digitalWrite(LEDG, HIGH);
      digitalWrite(LEDB, LOW);


Thank you very much!

public service announcement arduino rp2040 cant be used with micropython. pi pico, sparkfuns and adafruits can.

your trapped in the land of slow spi. its still 16 mhz max speed. it so sad. adafruit pretending their spi speeds mean anything for rp2040 boards. its slower that due

Please can you dra a circle around the Pin :slight_smile:

@michaeljohannes this one:

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