That's right, no hub, so the network setup is really simple in that case: just one straight cat6 Ethernet cable.|
Should the cmdline.txt be considered a legacy file, unused by the Banana Pi? Because the uEnv.txt file seems to follow a very similar structure. For testing, I added "ip=169.254.76.76" at the end of the file, and I got the same behavior as the Raspberry Pi, namely using the address provided as its local IP.
However, comparing with the Raspberry, editing cmdline.txt on the RPi, and uEnv.txt on the BPi, both work with a local IP address, with the same straight cable.