Apple recently released iOS 4.0 software update for iPhone 3G and iPhone 3G S. New software includes several features that are selectively available in iPhone 3G and 3GS. Unfortunately iPhone 3G doesn’t support all features of the OS 4.0 update due to the limited memory resources. You can now download the latest update from iTunes software after connecting your iPhone 3G or 3G S to the the internet. Other option is to download the software directly as IPSW files and update the offline through iTunes.
When you use the first method chances are high for disconnection and you would would need to restart the download again. So it is always recommended to download software update file directly from the Apple servers and update it using Shift+Restore process in iTunes. We can later use the IPSW file for unlock or jailbreak process.
Feature of the iPhone 3G or 3G S software update 4.0.
Download iOS 4.0 firmware update here.
Download iOS 4.1 software update here.
Download iOS 4.2.1 software update here.
If you are looking for iPhone OS 3.0 download, follow this link.
We will post more software update links for iPhone 3G or 3G S as soon as they are available.