Activation 1.1.2, For Windows
Step 1: To activate iPhone 1.1.2, you need an iPhone that went through the downgrade before firmware 1.0.2 or 1.1.1.
Step 2: Open the Installer and install OktoPrep (Tweaks 1.1.1 section).
Step 3: Open iTunes and click update (do not click restore!) Phone firmware to 1.1.2.
Step 4: Now install iPHUC and Java Runtime Environment (JRE) v1.6 (update 3).
Step 5: After you have installed the downloaded packages, then download and install Jailbreak 1.1.2. Next, run the Windows.bat file and tick the Install SSH checkbox and click Jailbreak. The process will take some time.
Step 6: Next to the Installer, section Tweaks 1.1.2 and install iWorld. Exit, launch iWorld and select your country.
Step 7: The phone is activated.