I have the following strange situation, where SerialPort>>nextPutAll: hangs when sending to a COM port that is (USB) connected to a Raspberry Pico (RP2040). The Pico contains a simple program (sketch) that echoes all input on it USB-serial port. This is written with the Arduino IDE. The echo function works OK with the Arduino Serial monitor, PuTTY and a simple Python progran. When I put the same echo program on another Arduino board (e.g. Uno or Adafruit Feather) Pharo's SerialPort does work fine. I have tested with 32 and 64 bits versions of Pharo 5, 7 and 8. All on Windows; on Raspbian there is no problem. So, there is something peculiar with the combination of the SerialPlugin and the USBserial implementation on the Pico (which uses TinyUSB), but I am at a loss as to where to search. Maybe somebody has a hint. I have seen problems with the Serial Plugin in the past. I ran into this when developing a driver for the Raspberry Pico, where the Pico runs the picod daemon (http://abyz.me.uk/picod/index.html). This code is in https://github.com/robvanlopik/picod-pharo and does not work on Windows. Rob van Lopik