I was having a problem with my AntMiner S3+ that had become unresponsive and inaccessible after I ticked a wrong check box while trying to get fancy with the network config.  I was trying to connect the miner via WiFi, and also use it as an access point for my Raspberry Pi that's running a Gridseed, and I bridged the wrong two interfaces.  I've seen a lot of posts in this thread with suggestions on how to fix it, but they are all either incorrect, incomplete, or unclear.

First off, no amount of fiddling with the reset button did anything at all, and I tried for many hours.  Pressing the button once does nothing, holding it down for >10sec makes it restart as does double-clicking it, holding the button and then starting it up will just cause it not to boot.  Someone said to start it, wait 3 minutes, hold the button for 15 seconds, do that again, and power cycle it... which didn't work, either.

I was able to fix it by connecting to the serial debugging port on the interface board with a USB to serial adapter, and editing the /etc/config/networking file with the correct settings and rebooting.  The post that gave me the hint about the serial port was a little ambiguous on the TX/RX pinouts, so I wanted to post a pic that should be self-explanatory.  I'm using a Parallax 'Propeller Plug' that I got for about $10 when I built a Propeller on a breadboard.  The driver makes it show up as a regular COM port, and I used PuTTY under Windows to connect to it.  The pin headers are just sitting in there, the worst that might happen with a loose connection is some corrupt characters in the terminal.  The reset pin is not needed.

Hope it helps!