After several hours of trying different methods I just found solution that worked for HP Compaq nx6310:
Just disconnect the wire. That's all.
Seems that there is a sensor in the Ethernet slot that disables wlan when a cable is present.
Because I even tried downgrading rfkill package to 0.3.x with no difference. Or similar mechanism was implemented somewhere else in Ubuntu. If so, then it should notify user about such behaviour.
After several hours of trying different methods I just found solution that worked for HP Compaq nx6310:
Just disconnect the wire. That's all.
Seems that there is a sensor in the Ethernet slot that disables wlan when a cable is present.
Because I even tried downgrading rfkill package to 0.3.x with no difference. Or similar mechanism was implemented somewhere else in Ubuntu. If so, then it should notify user about such behaviour.