I have now successfully downloaded and uploaded a Baofang UV-5RA using a Raspberry Pi and using a NanoPi Duo, with not USB dongle. The programming cable consists of three wires and the connectors at each end, and nothing else.

function radio Pi GND 2.5mm SP sleeve GND Data FROM radio 2.5mm SP ring RxD Data TO radio 3.5mm MIC sleeve TxD

Run CHIRP on your RPi, and it just works.