HA2NON
Here's a quick tip on setting up the OS2 both for home and phone Wi-Fi connections:
Go to the Network page, Wireless settings section on the OS2 web interface. Make sure Advanced mode is turned on (there's a checkbox for that at the bottom right of the web interface). Set your home Wi-Fi as SSID #1 (and key) and your phone's Wi-Fi as SSID #2 (and key). If your home Wi-Fi (SSID #1) is not reachable then the openSPOT2 will automatically try to connect to your phone's Wi-Fi (SSID #2).
Make sure you enter passwords case sensitive.