httpv://www.youtube.com/watch?v=5yO2KQHkt4A&feature=player_embedded
The hack uses Open iBoot to load the Android ROM during boot time. Looks like you can Dual boot between iPhone OS and Android OS.
If you still have first gen iPhone lying around this hack is worth trying if you are interested. This is possible on the iPhone 2G which was released in 2007. Support for iPhone 3G is coming soon. 3GS support might not be coming.
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