If FlowIO is not Recognized, this may be the Reason
I previously assembled the Flow IO by myself and wanted to code it through Arduino. However, I failed at the first step. Previously, everything was normal when I connected the Flow IO with a Micro-USB cable. This time, when I used the same Micro-USB cable that I usually use to charge my camera and phone to connect with the Flow IO, Arduino could not recognize it.
Finally, I found that the cable itself was the problem.
Although this problem is small, I hope it can help other users.
1. First, I connected it to the USB port of my computer while Flow IO was on. Then, I couldn't see the port in the list on Arduino.


2. Then, I changed to another cable. Then it still couldn't be recognized.


3. So now there are three possibilities: either my laptop's USB port has a problem, or this cable is faulty, or the Feather board itself is broken. Since I had previously used this cable and laptop to connect to it normally, I began to troubleshoot the connection to the microcontrol board.
Firstly, I connected it to the GUI, and it was fine.

Then Ali suggested me to try to connect it in user mode. The specific operation is to press the power button and the hole in the middle of W key at the same time while it's turned off and connected with Micro-USB. Then it will enter a strange mode. LED turns Red. But it is still not recognized in the arduino's list.
And in this case, you first hold down the small hole in the W, keep it, then press the power button