What was corrected by an update? The yellow band or yellow screen? Every persons device has a different stain of yellow so nothing they push out is going to solve their problems. And when it comes to the band, is it possible to only change colors on a section of the screen?
Yellow band = hardware
Yellow screen = software
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Oppo admitted their yellow screen was a hardware issue & accepted returns. Few people say that their Oppo suffers from a yellow discoloration now, but tons say their OnePlus One has it. Coincidence?
OnePlus refuses to accept that the yellow band is a hardware issue, and when mentioning of "yellow" it's assumed by them that you're talking about the entire display being yellow. Which they say it's because the actual display (they wanted it "warm"), or because the lighting was so close to the screen (They often flip-flop between these two things).
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Look for an official press release photo from OnePlus that shows the screen without on-screen keys. You won't find it.