This is a bit of a confusing one, but we just got tipped an additional shot of this 4th generation iPhone that leaked out in Vietnam, but this time with a big twist: it appears to be running iPhone OS 4. Or at least displaying a screenshot of the new OS, with that telltale wallpaper in the background. We have no idea how this crew might’ve circumvented Apple’s lockdown of the device, and there’s always the chance this is some sort of Photoshop or other trickery. Still, a source has confirmed to us that the markings “N90 PRO2” indicate an older prototype N90 (the Apple codename for the new iPhone), which refers to “Working Prototype 2” and might possibly be easier to enable than the newer, lock tight model Gizmodo obtained. Also, despite the photo’s out-of-focus nature, the display (or at least its contents) doesn’t appear nearly as sharp as those previous shots we saw of the “fireball” screen. We’re digging for more info as we speak, but unfortunately the original source site, Taoviet, is down right now. We’ll keep you posted if we hear anything else about this image’s origins.