Okay, so it sounds like the serial problem is solved, but something else is wrong (more on that below).

strace is a program to trace system-calls, you run ‘strace node-red’ and it logs all the operating system access that the application makes. We’re looking for calls to “open” and “ioctl” on /dev/ttyUSB0. This could tell us whether node-red is using the special io-control operations to set the terminal flags.

You can also use stty to view, the port settings while node-red is using the port.

   # stty -a </dev/ttyUSB0

The above will show the port settings.  You're looking for two flags "clocal" which means ignore the DSR/DTR pins, and "-rtscts" which means ignore the RTS/CTS pins.   Properly configured software can avoid the need for hardware loopbacks, but if the loopbacks

So now onto your crashing1:

I've been using node red, firmata and FTDI-based arduino with no random crashes, so that's one (anec)data point.


There are two things to check.

1.  You might be running out of memory, and triggering the out-of-memory killer (aka oomkiller).

Try this:

# grep Out.of.memory /var/log/kern.log

I *am* running out of memory from time to time, as I have some first-generation 256M and 512M pis, and the kernel kills the fattest process when this happens, often node-red, eg from my own log:

Jul 12 20:51:34 tweety kernel: [209492.223315] Out of memory: Kill process 408 (node-red) score 212 or sacrifice child

2. is node-red telling you why it crashes, or what it was doing right before it crashed?   Try this:

# grep Node-RED /var/log/daemon.log | tail -100