The size of iOS 2 (originally called iPhone OS 2), released in 2008 with the iPhone 3G, is not directly specified in the search results. However, it was an early iOS version providing major features like the introduction of the App Store and support for enterprise features. To give some perspective, modern iOS versions like iOS 18 now occupy around 18 GB on devices, but these include many years of additional features and system improvements. Typically, early iOS versions were much smaller in size due to less functionality and simpler software architecture. If more precise data on the exact size of iOS 2 is needed, it may require checking Apple archives or historical developer documentation, as it might not be readily available in public summaries or recent web content. Would you like me to search for more technical or archival sources about the specific installation size of iOS 2?