Download current and previous versions of Apple's iOS, iPadOS, watchOS, tvOS, audioOS and macOS firmware and receive notifications when new firmwares are released.
Install the latest version of iTunes from the Microsoft Store. Plug your iPhone 4 (GSM / 2012) in to your PC. Open iTunes, and navigate to your iPhone 4 (GSM / 2012). Hold the Shift key on your keyboard, and press "Restore". Select the iPhone3,2