Hey @goingalong,
It is a problem. I had the same problem with the Core and I added a function that check if the WIFI is connected or not, and if not, you can enter the wifi credentials with CoolTerm terminal. I think it is an easy solution if you can connect USB from your device to the computer. Another option is to burn program with WIFI.SETCREDENTIALS() and then change the wifi.
I hope with the photon and the softAP it will be easier… I’m still looking for the solution.