Hi, As i write in this post i've send back my n9 to vendor 'cause I think 802.11n problem is due to hardware. so, I only write here for your information ... As many N9 users I know that I'll have to "bidouille"/hack it to have the best phone ever, but, if something like wifi donesn't work properly ... It was very difficult to manage my email account, update mail box (only headers), read mail and get SIP account working over wifi ... I didn't read anything about any link between screen lock and wifi but, in my test to make it work i used ping (ping -t rm696) rm696 is default dns name of n9 on my local network. ping lost many packets, until my n9 get in "spleep mode" (screen locked after few seconds) and suddenly all pings came back ! I Unlocked phone and again, ping get lost, I locked screen and ping came back ! Of course, as I was running these experiments, all my mails were downloaded, my SIP account connected and so on ! but of course, unable to download mail content when screen is on and SIP get in netwok search mode Of course, in connection manager, wifi appear to be connected with good signal strength. I use 300mb/s 802.11n network with wmm active on a netgear wnap320 I really think it's a hardware problem due to screen.