Now that the government says it’s okay to jailbreak your iPhone, you can follow these instructions and install the Flash on your iPhone 4 that Apple engineers forgot to, without fear that the ninjas are gonna getcha.
The tweak involves jailbreaking your iOS device, installing OpenSSH and Cyberduck or WinSCP and then installing the Frash program. If you don’t don’t know what jailbreaking is, you probably shouldn’t do it, and remember that doing so voids your warranty.
Flash / Frash Ported to iPhone 4 !! [Redmond Pie]