Is it possible to put older firmware version on iphone

[katelmesser]

Is there anyway to install an older version of iphone's (using 1st generation) firmware? I have downloaded a 2.0 file with the "ipsw" extention. It doesn't open when click on.

[Tallest Skil]

Yeah, you can't just open it. It's not written in UNIX.

Option-click "Restore" in iTunes and choose the firmware from the menu. You really don't want to go back to 2.0, anyway.