If that's true then the background is 100% out of character for Apple. I don't speak Vietnamese, so perhaps he explains that part (i.e., he loaded his own software on it), but I don't think an Apple-provided diagnostic would look like that.
I believe it. Apple device diagnostic modes are usually extremely rough. You can put iPods into diagnostic mode. It's just unadorned text, and, on older iPods at least, you had to click the forward and back buttons to scroll through the menus. I remember seeing a different iPhone test screen that was similarly unrefined.
Apple's 'character' is to have things looking good by release, not necessarily internally.
I've seen their diagnostic modes plenty of times, and they don't look like that. I've seen them on iPods and on my laptop, but they don't have a shiny background on them that's totally outside their design aesthetic. That's what doesn't look right.
