Got your Apple iPhone unlocked? Then don’t upgrade to the Apple iPhone OS 2.2, as although it doesn’t appear to be a worldwide issue at the moment, but some iPhoners are reporting that the iPhone 2.2 update has locked their legally unlocked Apple iPhone.
It appears that this locking issue happens if a legally unlocked Apple iPhone is purchased in one country then updated to OS 2.2 in another country. So far countries reporting this issue are Hong Kong, certain European countries and others.
Reports coming into an Apple discussion thread go like…I bought my iPhone 3G legally unlocked from HK, and I just upgraded to iPhone 2.2, but it seems my phone is locked now. On the phone it says emergency calls only and iTunes is saying not supported SIM.
Source — iphoneatlas