As far as I know, "Serial.println("Hi")" will transmit data to the default TX serial port, which is Pin 1 as shown in (https://raw.githubusercontent.com/DexterInd/ArduBerry/master/Arduberry_hardware_description.png)
In the schematic, Pin 1 (TX) and Pin 0 (RX) are NOT connected to raspberry pi.
However, I could read the serial data by running a simple python script on Raspberry Pi 3 with the original Jessie.
I am not sure how this is possible. Are Pin 0 and 1 connected to Pi?
It is important to me because I want to put a wireless shield to Arduberry, which gets data from Arduberry through those RX and TX pins.
Thank you for reading my post!