as far as i know, iPhone from Singapore and Malaysia is officially unlock. no matter u use if on Digi or Maxis or Singtel, it still will work. Regarding JB, I wouldn't JB my iPhone now, Apple has declare that if you JB your phone, your warranty will be void. I know that most of you will say i am Bullshitting. Believe it or not, its up to you. At this point of time, there is no way that Apple can detect if your phone has been JB before. But in the future, they will.