Arduino nano Watchdog timer

I have a question. I#m using a watchdog timer this way

#include <avr/wdt.h>

void setup(){


void loop(){
//do stuff here


Problem: When the "stuff" is taking too long and the wdt is not served, so the CPU is not rebooting, but its hanging an the LED "L" on the pcb is blinking fastly.
What did I wrong? Thank you very much :slight_smile:

You forgot the code tags, or tell us anything useful.

Do a search on "arduino nano bootloader wdt bug"
There is a known compatibility problem with older bootloaders and the Watchdog timer

Thank you very much! Thats the answer I needed! Many , many thx :slight_smile: