3GS Unlock 4.2.1?
I am running an jailbreaked/unlocked 3GS still with OS 4.0.1. I need to keep the unlock, but would like to upgrade to any of the newer OS versions, preferably 4.2.1, of course.
Can this be done? Jailbreaking seems relatively easy, but the only unlock guides I seem to find are for the iPhone 4. I have also seen some articles about using the iPad baseband, which seems to kill the GPS. Is that still the case?
My baseband is 05.13.04. I only have access to a Windows machine.
Thanks for help!