On counterfeit SD cards

[jl_678]

Fake/counterfeit SD cards are a real concern for anyone trying to buy a reliable SD/TF card. You get them from every retailer since they sometimes don't even know that they sell fake cards. And trying to make 'good deals' almost always ends up with a fake SD card.

Compare with this nice article here:

I recently got about 20 64GB Micro SD cards for some project at various online sources (eBay, Ali, etc). 17 of those cards are fake.

17 out of 20. Hey, that's only 85 percent!

Fake/counterfeit SD cards have less real capacity than the controller signals (most of the times they are also way slower than they should be). So if you insert this card into your PC it shows 16 GB capacity while it might be just 8 GB in reality. This card will work more or less fine until you exceed the 8 GB limit.

What does this mean for burning Linux and Android/RemixOS images.

You will be able to burn any Linux OS image that doesn't exceed this size without any errors. You can also later resize the rootfs to the faked capacity still without getting any error. But you will get in trouble for sure if you start to write data on the card the moment you exceed the card's real capacity since data that will be written beyond the card's real capacity is lost. Filesystem errors will occur, the FS will be turned read-only, applications and the system might crash/freeze. But this will happen later when you try to use the Pine64.

With Android/RemixOS it's different. Android images are meant to be burned using Phoenix Card. This tool tries to detect the card's capacity, then formats and partitions the card in a way that the whole capacity will be used. The size of all partitions is fixed except of the data partition. This will be resized to the max. Since the data partition is somewhere in between the other partitions Phoenix Card will move some partitions beyond the card's real capacity if you got a counterfeit card. In this case Phoenix Card will already fail burning the system partition so you will end up with the last message "[boot]Burn success" followed by a single line containing "Error" (when the Error is thrown Phoenix Card has tried to write the system partition and then tried to verify a successful burn by verifying checksums... and fails here):



So if you run into this situation think about testing your card now. Most probably you use a fake card and in case you used it before simply didn't take notice due to the different useage/partitioning. A fake card could be used with a Linux image on a Raspberry Pi since years without a single error but will fail already when trying to burn an Android image with Phoenix card due to the totally different partition scheme used by Android.

This is all well known since years and the Pine64 folks should create a quickstart guide that recommends testing every card prior to useage. It's easy and will save you time and hassles.

Hi,

I see all these comments about counterfeit cards and it makes total sense.  However, there is one thing that confuses me.  It is clear that if you purchase cards from questionable sources (asian online marketplaces, eBay, etc...) that the likelihood of counterfeit goes up astronomically.  However, what if you only purchase brand name cards directly from reputable sellers like Amazon and the like.  Obviously, there is no guarantee, but I think that the likelihood of counterfeit goes way down.  Right?

My $.02 is that it is worth spending a few bucks to buy a card from a known vendor and avoid the headaches later, but that is me.