I have an iPhone 3G, iOS 4.0.1, jailbroken using jailbreakme, unlocked using ultrasn0w 1.1-1, with a Virgin Mobile UK sim. The odd problem I'm having is that I only get signal when I turn ON 3G. Cellular Data remains off, but if I turn off 3G, then I get 'No Service'. Can somebody explain this? And is there a fix? Thanks.