Vito Cassisi – Tech Blog Delving into technology

Avoiding and testing for fake flash drives – eBay

Sometimes you've just got to use eBay. Here's how to do it safely.

Buying flash memory devices on auction sites is risky business. It may appear that the listing offers a large capacity product for insane prices, but reality is, there's very little chance that it's the real deal. Originally scammers would flog off devices with no electronics inside. Playing such a primitive trick is all too obvious, even a layman could quickly and easily identify the root cause within minutes.

It didn't take long for an influx of low capacity flash drives with modified memory controllers to come into play. The alteration creates the illusion of a larger capacity. It does this by reporting a large capacity to the operating system, regardless of the true capacity. The flash drive is still functional - up to a point. Writing past the true capacity leads to corrupt files and read/write errors. Most people won't even realise until well after they've given a 5 star positive seller rating.

The nature of this dirty practise makes it very difficult to spot a fake. Nonetheless, there are ways to both prevent and to solve potential issues.

If it's too good to be true, it is
You're not going to get a top-of-the-range product for pocket change. Have a look at price search engines such as StaticICE. If an eBay product is well below market value, there's a good chance that it's a phoney.

Check images of the packaging
Have a look at images of the packaging (e.g. on Google Images), and compare them to the listing. If they look unusually different, then it's possible that the product is a cheap rip-off. Keep in mind that a single product may have multiple legit packaging styles.

Ask the seller
You'd be amazed how often this works. Ask the seller if the product is a 'genuine <insert product name here>'. Most will beat around the bush (so to speak), and will reply with something along the lines of "if not sure, don't buy". Wonderful, don't buy it. :)
Unless the seller specifically states that the product is genuine, don't go near it.

Check the feedback
Don't just check how many positives they have, go and read all the negative testimonials. It's a bad sign if several buyers have complained without a valid seller response. It may also prove useful to read the positive claims too. To save time, focus on the entries relating to the product you're purchasing.

Read the description carefully
If the description for the product is very vague, and leaves out important information such as brand name, model number, and technical specifications, then seek clarification with the seller. If they're of little assistance, don't pursue the matter. There's little point dealing with someone who struggles to assist concisely. This may sound harsh, but remember who it is you have to deal with when something goes weary.

Check where the device is coming from
It's highly recommended that you buy from your country of origin (unless it happens to be the source of counterfeit items). Hong Kong users generally sell fake or inferior items. When it comes to flash memory, it's best to avoid them.
It's also much easier to claim warranty (if applicable) when the product is from a local seller.

So now you've bought your new flash drive, and it's in your possession. It's a good idea to check that it's legit. If the packaging looks fine, and the product is in good condition, it's off to test its true capacity!

Testing a flash drive - What you'll need
- A few large files that'll be able to fill the flash drive
- MD5 checksum tool (MD5 Checker)

Testing a flash drive - Method

1. Connect the flash drive to your PC.




2. Format the flash drive to either FAT32 or NTFS. Keep in mind that FAT32 has a 4GB size limit per file, so you may have to use several smaller files in the upcoming steps for a high capacity device. You can format the drive by following 'Computer' > right-click drive name > 'Format...' then hit 'Start' once you've chosen your preferred file system.




3. For an NTFS based flash drive, you may find it's easiest to zip a bunch of large files together to fill up the advertised storage capacity. Since an 8GB drive may really be 7.4GB formatted, my general rule is to select an odd number immediately below the claimed storage capacity. e.g. use 7GB of files on a 8GB drive, 3GB on a 4GB drive, 1GB on a 2GB drive etc.




4. For a FAT32 drive, do the same as above, but in maximum files sizes of about 3.5GB. So for a 8GB drive, you'd need two 3.5GB files to fill it to 7GB.




5. Run MD5 Checker. Click 'Add' to input the file(s) you will be using to test the flash drive. Note the 'Current MD5' for each file.




6. Copy the files(s) onto the flash drive. If an unexplained error occurs, attempt to resolve it. If you cannot find a solution, it may be a counterfeit drive.




7. If the files transferred successfully, check their MD5 checksum (whilst on the flash drive) using MD5 Checker. If they're identical, the advertised capacity is correct.




8. For added assurance, copy the files off the flash drive, and check their MD5 checksums again.

Additional testing
If you're still not convinced, testing the transfer speed of the drive can help distinguish a genuine flash drive from a fake. Using HD Tune, test the read/write speeds of the flash drive. Keep in mind that the specifications listed by the manufacturer are theoretical, so don't expect performance exactly as advertised. However, if the flash drive is rated at 30MB/s read, and the tests show 10MB/s read, then that is a concern. Ensure your PC meets the requirements of the flash device, for example, USB 2.0 for modern USB flash drives.

Follow these simple steps and you're bound to get yourself a bargain, without the headaches and disappointment of a fake product. Happy bidding!