Hey guy's... I'm not good at this... but... :) there are 4 pin locations on the board Gnd/ rx/tx/5v that in many cases do not have the risers installed... I am going to say you are using the USB mini port for communication to the board... which in many cases is the appropriate way... One of the symptoms I am seeing in my boards not appropriately flashed.... is when restarting the computer the com port for the Control Board establishes...

Before you plug in the board... go to your Devise Manager and see what active ports exist BEFORE plugging in the board. This will get you more inside what is going on.

I can read a board.. and connect to it in an old version of the GUI... ( which sucks for me... and I am learning to upgrade flash this older board as we speak ) ( I have newer boards as well ) When trying to flash or read flash gives me an error message... at this point I lose all port communication in that port. Needing to restart the computer in order to refresh the ports with no control boards plugged in at startup... The control card port should no longer be established in the port dropdown list in the Device Manager.

When you lose all communications with the USB mini port... using the usb pin configuration on the board... has provided me with contact to the control card port not accessible via usb mini.....

When plugging in a separate ( different ) gimbal control card... the computer establishes a separate com port because it is a different board.. when the first board IS NOT PLUGGED IN TO THE COMPUTER...

It is always recommended to have the IMU plugged in. In some cases it may hinder the connection configuration status... " READY " In order to continue processes..