This is a card that I found while browsing through microSD cards on AliExpress. I was curious to know whether there were any sellers selling both fake flash and authentic flash under the same brand name, so I purchased a 16GB and a 2TB card from the same seller. I expected the 2TB card to be fake — but in reality, they were both fake.
Disclaimer: I don’t think Xiaomi had anything to do with this card. I think this is an unlicensed knock-off (hence why “Xiaomi” is in quotes).
In my experience, sellers who sell knockoff cards usually follow a pretty similar M.O.: they steal the name of a well-known, respected electronics manufacturer who isn’t particularly known for selling flash media (or usually any storage media whatsoever). In this respect, Xiaomi was a prime target for these sellers. (If you’re not familiar with Xiaomi, they’re a huge electronics brand in China — many have dubbed it “the Apple of China” — but from what I can tell, they don’t sell microSD cards or any data storage products whatsoever.) They then siphon some of the established brand’s reputation and use it to make money for themselves. Why do they target manufacturers that don’t sell flash media? I don’t know — perhaps they’re just targeting large, respected brands; or perhaps they’re doing it so that it’s harder to disprove that their product is genuine. After all, if there’s no genuine article to compare it to, then it’s harder for someone to say that a knockoff product isn’t genuine.
Performance metrics were — as to be expected — pretty abysmal. All performance metrics were below average, scoring in the bottom 15th percentile. Scores were not good enough to qualify for any of the performance marks that it bore. I’ll throw in my standard disclaimer here — my performance testing doesn’t align with the tests prescribed in the SD standard, so it’s possible that this card would have done better had it been tested under proper conditions — but I highly doubt it.
On the endurance front, this card started having issues almost immediately. During the first round of testing, a 1.8MB “hole” appeared, where reads from sectors in the hole resulted in all zeroes being read back. This hole persisted in size and location during subsequent rounds. Several more such holes (of varying sizes) appeared during subsequent rounds, but did not persist for more than a few rounds. Additionally, data verification failures happened during a few rounds of testing, affecting ranges in size from a few hundred kilobytes to several megabytes. Curiously, however, these issues stopped between rounds 1,599 and 5,239 (with the exception of the original hole discovered during the first round); at this point, the card began to suffer a lot of bit flip errors. It finally failed during round 6,619 — when any attempt to write to the card resulted in an I/O error.
Given that the hole that appeared during the first round of testing — which I’ll call the “origi-hole” — persisted during all rounds of testing, and combined with the fact that all subsequent errors happened after the location of the origi-hole, it could be that the origi-hole marks the end of the intended physical space, and that the remaining space is being used for wear leveling. I haven’t seen any other cards exhibit this kind of behavior. If that’s the case, then the true size of the device would be 3,824,201,728 bytes instead (about 200MB smaller than what I originally calculated). But…that’s just my guess.
Overall? It’s a knockoff, it got terrible performance, and it didn’t do that well in endurance testing. Don’t buy these — they’re trash.
June 10, 2025