now I'm on iPhone 4 baseband 01.59.00 and iOS 5 semi-tetherd and is been great. I'm upgrading on the 25 of nov to the 4S and selling my i4 on eBay. the resell price of an unlocked i4 is around $350 to $450 depending on the condition of the device. so i think is worth the baseband preserve. I'm semi-tethered with only MY3G, SBSettings (be cautious when using SBSettings some features made my i4 overheat and drain the battery. i think it was the delete carrier in system options but I'm not 100% sure), and TetherMe works perfect and had no problems.