I have an Adafruit 5V Buck power board that I will be using to power my Adafruit Feather. I will supply 12V to the Buck board and then use the 5V output to power a sensor and to power the Feather which is connected to the 5V from the Buck through the USB connection on the board. I need to download the program for the Feather from my computer over the USB port. I expect that I should not connect the USB from my computer when the 12V is connected to the Buck because that would be back feeding the Buck with the the 5V from the USB port. BUT, the question is: If I turn off the 12V connection to the Buck, can I use the USB 5V to power the board (but not the sensor)? I'm still back feeding the Buck but since the buck is not active it may be alright??? What do you think?