Yun unavailable after upgrade

Hi, I have a Yun that I am having considerable amount of trouble with. In trying to deal with a network problem I ran into advice on the forums and from friends that suggested that I make sure the firmware was updated (I had a 2013 board I think). I upgraded as according to the site (https://www.arduino.cc/en/Tutorial/YunSysupgrade). Everything appeared to go well, at least as far as I could tell, but after performing the upgrade, there was no sign of the Yun. The IDE could not find it, directly entering the IP address assigned to the MAC address cannot find it, there was not new arduinoxxx SSID (or anything similar). I just can't find any trace of it.

Now, when I plug in the Ethernet cable the WAN light blinks as expected, the ON LED is solid, the USB light comes on when pushing the Yun RST button, the slow red fade shows as expected on the 32U4 double click, but… I still can’t find it.

I have tried... wifi or cable – using the IDE, looking for an arduinoxxxx wifi, looking for its wired/wireless MAC addresses on terminal/arp, etc. I have tried on OS X and PC, and have made sure I have updated the IDE's in each OS. I have tried the 5 second reset to reset the network settings, the 30 second reset to get back to factory settings, and a variety of other resets.

I have done network and computer restarts, etc. and have waited a couple of days to see if DHCP renews and refreshes took care of it (and give myself time to research and brainstorm). I have searched on the forums and elsewhere to see if there were similar issues. The closest I found was this, but even this requires that I be able to upload a sketch, which I can't do until I am able to locate the Yun.

Please, any thoughts? Any help would be appreciated.