Long print crashing on Arduino Nano 33 BLE

I ran across a problem trying to run several IMU calibration sketches. They kept crashing the application and the Mbed OS. (When the bootloader crashes, it blinks 4X short 4X long on the yellow LED).
In playing around with debugging it, I reduced the issue to trying to print more than 64 bytes with a single print statement.

Here is some code that will demo the problem:

void setup() {
  pinMode(LEDR, OUTPUT);
  pinMode(LEDG, OUTPUT);
  pinMode(LEDB, OUTPUT);
  digitalWrite(LEDR, HIGH);  digitalWrite(LEDG, HIGH);  digitalWrite(LEDB, HIGH);  // turn the LED black 
  Serial.begin(115200); 
    digitalWrite(LEDR, LOW);  digitalWrite(LEDG, HIGH);  digitalWrite(LEDB, HIGH);  // turn the LED red 
  delay(1000);
  while (!Serial);
  Serial.println("Serial opened");
  digitalWrite(LEDR, LOW);  digitalWrite(LEDG, LOW);  digitalWrite(LEDB, HIGH); // turn the LED yellow
  delay(1000);
  Serial.println(F("         1         2         3         4         5         6"));
  Serial.println(F("1234567890123456789012345678901234567890123456789012345678901234"));
  Serial.println(F(".........this works fine........................................"));
  digitalWrite(LEDR, HIGH);  digitalWrite(LEDG, HIGH);  digitalWrite(LEDB, LOW); // turn the LED blue 
  delay(1000);
  Serial.println(F(".........this causes a crash....................................."));
  digitalWrite(LEDR, HIGH);  digitalWrite(LEDG, LOW);  digitalWrite(LEDB, HIGH); // turn the LED green 
}

void loop() {
}

When running the code, you will see that instead of the LED completing the pattern of black/red/yellow/blue/green, it will do black/red/yellow/blue and then the yellow LED will begin the 4x short/4x long blinking sequence, indicating that the Mbed OS has crashed, and you won't see the last line printed in the Serial Monitor.

In case you try this, after a crash, you need to double-click the reset button in order to restart the Mbed OS (you will get a pulsing yellow LED), and then upload a new sketch that won't crash.

I have also tried doing this removing the F() function, but it doesn't work either.

This has been reproduced on two different Nano 33 BLE's as well as on both a Mac and a PC.

Any idea why this print crash is happening?

Also, as a side question, why do I have to turn my LED's to HIGH to turn them off, and LOW to turn them on, when every other code example shows the opposite? This is in reference to the built-in RGB LEDs on the Nano 33 BLE.

"why do I have to turn my LED's to HIGH to turn them off, and LOW to turn them on, when every other code example shows the opposite? This is in reference to the built-in RGB LEDs on the Nano 33 BLE"

Because they are pulled high (to 3V3), see section 'B5' ↓

cdeerinck:
I reduced the issue to trying to print more than 64 bytes with a single print statement.

There is a bug report about it here:

pert:
There is a bug report about it here:
Crashing when writing more than 64 bytes to Serial · Issue #85 · arduino/ArduinoCore-mbed · GitHub

Awesome, looks like they fixed it already. Stupid question, but how does one update the MBed on the board? Can someone point me to a URL that would take me through the process?