I am relatively new to the YUN and not a computer scientist.
Issues I ran into when setting up my YUN on a macbookpro (old)
- I could upload and communicate via WiFi but not USB.
- I thought a fix for prob 1 would be to update OpenWrt, this seemed to brick YUN
- after recovering not-really-bricked-yun I still could not connect to myyun.local. I could ping but if I tried to SSH to yun IP I would get a unknown host_key rejection.
I first tried the Terminal OpenWrt method of upgrade. If OpenWrt system upgrade does not write (led not flashing) then YUN will appear bricked after upgrade "finishes". I could not communicate with YUN at all, no "myarduinoName".local page would work (arduino no longer connected to WiFi). So I power cycled Yun and after 10 seconds I pressed the 32U4 reset and reset WLAN (hold for a 10 count should be flashing) then wait some more. after this I was able to find the YUN in my network, and connect to it but it reverted back to "arduino.local" THEN i tried to name myYUN the SAME name as before, which I think messed up the known_hosts file in my mac. I did a bit of google fu and found this gem:
ssh-keygen -R 127.0.0.1 (Obviously replace with the servers IP)
Just type that in a terminal and I was back in business!
Then I was finally able to upgrade OpenWrt via the web page.
but still USB did not work for downloading sketches, so I checked forum and found another user who had same problem and it turned out to be a faulty USB cable that was working for power but not TX, RX. I swapped cables and now all is right with the universe.