alzhao
4
If you have a working image, you can upgrade using USB or wifi.
If you don’t have a working image, you can only upgrade using Ethernet.
So for production, we can assume that you are having a working image already, there is no need to have Ethernet. But for development, Ethernet is a basic requirement. Because you can easily broken your working image during development.
UART is used for interacting with the cpu but cannot be used to load firmware. So you cannot upload firmware to the board via UART.