Hi guys I have a 2 month old Nexus S and for no apparent reason all of a sudden today I noticed I am not getting any network service (australia vodafone). I've tried removing and trying other sim cards which are known to work. My sim card works in other phones so it's nothing wrong with the sim card. Wifi still works perfectly. I've tried going in and out of airplane mode to restart the antenna and I've tried to turn it off and on again. I've also done a factory reset and erased all data through the android menu as well as the bootloader separately to no avail. However what I also noticed is even though I did factory resets it doesn't seem to completely reset it as the android version still shows 2.3.3 which I applied using a manual update. The phone had 2.3.1 when I bought it. How do I do a full reset to send it back to 2.3.1? The phone is still under warranty however if it is a software issue I would rather fix it myself then send it away.