We have 2 WCDMA networks here in IRAQ but SGS2 I9100 cannot find any of them even when I'm choosing WCDMA mode from network operators, while it works fine with GSM. Why?
There are different WCDMA(UMTS) frequency bands. I believe that they use Band-I (2100MHz) in IRAQ. You did not mention which country you bought your phone in. But if it was anywhere in North America - I have bad news for you: none of american carriers use this band so very few phones sold here support it.