I bought an iPad air 2 (16gb wifi ) from Walmart in Nov. 2014. The speaker started having a 'popping sound' after 2 months while I'm using it. I brought it back to the Apple Store on Jan 2015 to explain the issue. They reset it to factory default and asked me to try using it again. If the issues were still there, they told me to bring back to them and they would replace it for a new one. After 3 more weeks, the 'popping' sound came back, so I brought back to the store and got my replacement. Again, the 'popping' sound happened after about 1 month from the replacement iPad 2, just not as bad as the original iPad. Last week I brought it to the Apple Store to explain the same issue (found out that before the other Apple store listed it as giving me a 64gb instead of 16gb), and said if I cannot replicate them the 'popping' sound in store, they cannot replace for me again or do anything about it. The problem is the 'popping' sound can happen at any time during the day while I am using it, so how can I show them at the store at that moment. I said I'd rather upgrade to the 64gb and was willing to pay the difference because I think maybe all 16gb iPad air 2 have the same issue. But was told that my iPad air 2 is too new it's not eligible for the Trade-in Program until a new iPad Air model is out on the market. By then my 1 yr. warranty will expire and my iPad 2 will only be worth $250 or less. At most, they'll offer half of the original price even if the device is barely used.
Store manager notice my original ipad air 2 is bought from Walmart, he then said no more replacement or upgrade.