wifi failled connection with yun and after upgrading openwrt I recently bought an arduino yun. When trying to connect to the router following the procedure in https://www.arduino.cc/en/Guide/ArduinoYun#toc14. After the Configure &amp; Restart, the Arduino network shut down after a few moments but it wasn´t linked to my router.

After reading a bit about it in the internet, i upgraded it following https://www.arduino.cc/en/Tutorial/YunSysupgrade. As i found that the firmware version 1.5.3 was from 2014 https://github.com/arduino/openwrt-yun/blob/master/ChangeLog, and as Reflashing the OpenWrt-Yun image on the Yún would void warranty, i proceeded by http://nootrix.com/software/upgrade-arduino-yun-openwrt/. Everything occured as detailled there.

However now, when i turn on the yún, none network appear and the WLAN LED doesn't blink.

Thanks
Find out if the Linux system is running. Maybe you mistyped your WiFi password.
Try the Following: 


connect via Ethernet check your router to see if the Yun request an IP via DHCP
If unsuccessful connect via USB and install this sketch to see if you get a command prompt maybe your network settings are messed up 


Still no success?


Press the WiFi reset button for at least 30 seconds to do a reset to
factory defaults.