I had a similar issue after restarting a Lenovo thinkpad T520 (iwlwifi on a Centrino 6205).
After a cold start, not all the time. Sometimes I needed up to 4 restart before the wifi connexion succeeds.
The solution described in bug 1590985 solved both issues:
wifi connection at startup _AND_ wifi restore after suspend.
Please have a look at this solution: https:/ /bugs.launchpad .net/ubuntu/ +source/ linux/+ bug/1590985
Post #9
I had a similar issue after restarting a Lenovo thinkpad T520 (iwlwifi on a Centrino 6205).
After a cold start, not all the time. Sometimes I needed up to 4 restart before the wifi connexion succeeds.
The solution described in bug 1590985 solved both issues:
wifi connection at startup _AND_ wifi restore after suspend.