Do I have to expose both USB ports to upgrade the firmware/system on Edison? This makes field upgrade design very hard
Anyway to upgrade via wifi?
We would like to know some more information about your concern. Do you plan to design a custom board for the Edison?
If you want to update the firmware on the Intel® Edison board via USB, you need to use only the USB OTG port.
Additionally, about using WiFi to update the Edison, we recommend you read this thread /thread/105153 https://communities.intel.com/thread/105153, and also we find this information https://gist.github.com/skvark/794217634c5024da9052 https://gist.github.com/skvark/794217634c5024da9052 that could be useful.
We hope this information helps, please let us know if you have any question.