Sleuthing uncovers the mystery of Kingston MicroSD cards' crappy QA

When Bunnie Huang was in South China overseeing production on his versatile ChumbyOne device, he discovered a major quality issue with Kingston's MicroSD cards. At first, he assumed that he'd gotten a counterfeit batch, but further investigation proved them to be legit. Kingston wasn't willing to give Bunnie any details on its QA process, so Bunnie did some amazing engineer-sleuthing on Kingston and its competitors' MicroSD, and wrote up the results in a damning report that is one of the most fascinating accounts of everyday engineering I can remember reading. Bunnie Huang wrote the book on reverse engineering, literally, so he isn't afraid to start dissolving memory cards' encapsulant with acetone, or start comparing /sys entries to get comparative reads on the the electronic card ID data records. Posts like this make me want to be like Bunnie when I grow up.

Furthermore, the manufacturer's ID is 0×41 (ASCII 'A'), which I don't recognize (supposedly the SD group assigns all the MIDs but I don't see a public list of them anywhere). The OEMID is also 0×3432, which is suspiciously ASCII '42′ (one more than the hex value for the manufacturer ID). These hex/ascii confusions are possible signs that someone who didn't appreciate the meaning of these fields was running a ghost shift making these cards.

Armed with this evidence, we confronted Kingston -- both the distributor in China as well as the US sales rep. First, we wanted to know if these were real cards, and second, if they were real cards, why were the serialization codes irregular? After some time, the Kingston guys came back to us and swore these cards were authentic, not fakes, but at least they reversed their position on not offering an exchange on the cards -- they took back the programmed cards and exchanged them for new ones, no further questions asked.

However, they never answered as to why their card ID numbers were irregular. While I know chumby is a small fry customer compared to the Nokias of the world, I think it's still important that they answer basic questions about their quality control process even to the small fry. I had an issue once with an old version of a Quintic part being accidentally shipped to me, and once I could prove the issue to them, I received world-class customer service from Quintic, a full explanation, and an immediate and full exchange of the parts at their cost. That was exemplary service, and I commend and strongly recommend Quintic for it. Kingston, on the other hand, did not set an example to follow.

On MicroSD Card Problems