The Serial Port connector is quite handy as a dev tool, however, it has always had some mysteries for me as a predominantly Mac user. I found it difficult to describe exactly the behavior I was seeing since sometimes it would simply work and other times not at all.
Tonight I found myself the most accurate threads on the internet to describe exactly the behavior I was able to hone in on and reproduce. If I want to use the Serial Port, I need to reboot my mac and have the FTDI connected. Once I disconnect the FTDI, and reconnect it, the Arduino IDE does not list it. And so it is no longer available to show my Serial output or receive Serial input.
Here is the thread: Rescan USB Serial Converter? - Apple Community
Has anyone else witnessed this behavior, had this same frustration?
Knowing this now, I will simply keep the FTDI connected to the machine and disconnect the adapter board when uploading new FW, this will keep me from needing to restart my machine with frequency. Hope this helps others and if we can find a nice solution to have the Mac or Arduino allow for this hot-swap, it would be wonderful.