Hello. I've encountered a weird problem with N9's GSM module (modem?). After a brief period of heavy internet use (internet radio or Spotify for example), say, 3 hours or so, N9's radio may sort of 'hang' so that there are bars which are fixed in whatever position they were, the operator name and I am unable to place or receive calls or SMS messages. Has anyone else encountered this problem? I heard some whisperings about people being aware of this problem but couldn't find any forum posts, except, oddly, the one related to N900 with exactly the same problem:
http://talk.maemo.org/showthread.php?t=49350

Rebooting the phone does fix the issue but the worst part is that the phone won't let you know what happened visually until you try placing a call. I brought it to be repaired and all they did was reflash the modem firmware which didn't help. I don't remember this happening on older firmware versions, then again, I could be using internet less.

get a new sim card. i'd a similar issue due to having cut my sim into micro-sim. got a real micro-sim and it got fixed.

Nope, it's been originally fitted with a microsim that worked fine in an iPhone but I've later replaced it with a brand new one to see if that fixed the problem - it didn't.

https://harmattan-bugs.nokia.com/show_bug.cgi?id=79

Wow, thanks slarti!