Yes. You need to read some tutorials. The steps are 1) Downgrade to 1.1.1 (by using recovery mode) and Jailbreak 1.1.1. 2) Run OktoPrep and upgrade (not restore) to 1.1.2 and then jailbreak. 3) Use the official dev 1.1.3 JB to upgrade to 1.1.3. then the final step 4) Use Geohot's gunlock to unlock the phone modem. Of course, the modem firmware will be downgraded to 4.02.13G (1.1.2).