Here is firmware to try. New commands:
antenna internal // selects the CHIP antenna
antenna external // selects the u.FL antenna
wifi_signal // Gets the signal strength as a percentage (0.0 – 100.0)
wifi_quality // Gets the signal quality as a percentage (0.0 – 100.0)
After changing your antenna, you must reboot your photon. The setting is “sticky” so it will remember your last setting. I’m curious if this helps!