Depending on how long you press the button the following will happen (I think):
- Pressing the WLAN Rst button for <5 sec does not do any reset at all, correct (it just lets a LED blink)
- Pressing the Wifi Rst button for >=5 but <30 sec will run the wifi-reset-and-reboot script. This script will return the Yun in access point (AP) mode and will reboot the Yun. The Yun should then present its network SSID.
- Pressing for >= 30 sec will restore some factory settings
If you just want to reset the Wifi, you can do this with the wifi script (should be in /sbin):
root@Arduino:/tmp# wifi down && sleep 5 && wifi Successfully initialized wpa_supplicant
You probably can also do:
ifconfig wlan0 down; ifconfig wlan0 up
Note that rc.local contains by default the entry wifi-live-or-reset. After the Yun boots, it will check for the configured Wifi network. If it is not found within 60sec, the Yun will go into access point mode.