Lately, many iPhone 4 users wonder if there is a free unlock solution for baseband 4.11.08 or 4.12.01 and how to implement it on their terminal. Well, unfortunately the answer is still no. At the moment there is no free method to unlock these iPhone 4 baseband's, of course, if previously you have not performed an unlock with SAM.
This question emerged after Dev Team successfully released a downgrade solution for iPhone 3G/3GS with baseband 06.15.00. Unfortunately, this downgrade solution does not work on all iPhone 3G/3GS terminals and sadly it is not available for the iPhone 4. read more

