Arduino Nano USB Serial Bypass I have a Nano clone here, that sporadically fails to get detected by my banana pi. This is annoying, because it works for days and hours, but fails to work randomly.

The Nano gets it's own power via VIN and thus should have enough power.

I thought of bypassing the FTDI and make a Serial connection via 2 Wires. Alternatively: Is there a way to force the arduino to use external Power over USB. I have the feeling, the the arduino wrongly decides, that USB is the better power source and uses it, causing the errors ( device not accepting address 21, error -62 )

P.S.: There is also a touch-screen connected to the banana pi via USB. Whatever port I use, It works and never failed. Just the Nano fails from time to time.
To answer this question

The arduino in question was broken. Shortly after asking I was not even able to connect it to my PC successfully. I replaced it with a new one and everything runs smoothly now for months.

Since this unit survived a whole product development-process I am not surprised at all. In fact I had three and expected one to get killed in action.