i finally unlocked (tmobile) my iphone 4, bb 03.10.01, 4.2.1, jailbroken with greenpoison, using the Gevey Ultra sim. No major problems except that when i try to watch a video clip its choppy and slow. I also fixed my mms, sms, and facetime no probs there. So is there a tweak or something somewhere that will speed things up? I am on wifi with full signal also. Sorry for so many details, just thought it would help. Thanks!
Did you check to see if it is anything from Cydia causing it? If that isn't the case and you can't find the source of the problem, you might consider restoring and rejb.
I wouldn't recommend trying to "tweak" it to make anything go faster just bc normally an iPhone 4 should not have this type of video performance. It should run perfectly smoothly if everything is normal.