How can I test if a USB thumb drive is fake?

I bought a 256GB USB stick for only $5 on eBay.

I know:

What could possible overwrite your sense of "hey wait a minute" as a technology person would make you think you could buy a 256GB flash drive for $5

I was asked many times already. However, I went ahead and ordered the item anyway and after shipping I really received it.

I tested the drive to see if this was too good to be true by copying 256GB of data back and forth - I could then see if this USB drive really has the 256GB it should have.

Of course, it did not. After writing more than 4GB of data I got this message:

enter image description here

I know I've been fooled (deliberately), but how was this done?

How can I test the drive and see what they really sold me and how they pumped it up to 256GB?

Caspar Kleijne

Posted 2011-09-30T06:50:44.703

Reputation: 495

1and he has 100% feedback – sealz – 2011-09-30T11:14:29.127

Big hint: Return policy: Yes, of cause!. Not to mention only 2 feedback. – Belmin Fernandez – 2011-09-30T11:56:56.357

1the person whom you quoted that from must be really awesome :D – Eonasdan – 2011-09-30T12:29:13.613

1If it sounds too good to be true.. – Jake Berger – 2011-09-30T15:03:30.813

Answers

Its been known to happen - most likely the drive has modified firmware or a modified fat table showing the wrong size. I'd image the drive for fun, then wipe the drive and reformat to get its actual size -if its that, its the fat table. Else it may be firmware

Journeyman Geek

Posted 2011-09-30T06:50:44.703

Reputation: 119 122

Editing the FAT table is (relatively) easy to do and requires no equipment apart from a Linux PC with a USB port. – skolima – 2011-09-30T14:18:38.093

1@skolima: s/Linux/Hex editor/g – Tamara Wijsman – 2011-09-30T19:14:55.267

You could probably use a Hex editor like HxD for Windows to edit the FAT table as well. Oh boy! I know what I'm doing tonight. – Phil – 2011-09-30T21:16:13.660

Simple Checklist:

Device listed on eBay
Price is too good to be true

Linker3000

Posted 2011-09-30T06:50:44.703

Reputation: 25 670

5How does this answer "how was it done"? – detly – 2011-10-01T16:30:20.857

Pry it open, read the chip number, and look it up.

Ignacio Vazquez-Abrams

Posted 2011-09-30T06:50:44.703

Reputation: 100 516

4I'm not sure if this is a good solution, if you want a refund (and to hassle the scammer). – dr jimbob – 2011-09-30T17:50:44.213

You could do this by having a particular sized disc, and formatting it to whatever you want the flashdrive to show. Then copy the first 512bytes with dd from the hard drive to the USB. The USB should report being huge now! D: I'll try it later.

Rob

Posted 2011-09-30T06:50:44.703

Reputation: 2 152

If the drive is formatted to FAT32, then the largest size for a single file is (about) 4GB. Try reformatting it to a different file system, like NTFS.

Ƭᴇcʜιᴇ007

Posted 2011-09-30T06:50:44.703

Reputation: 103 763

Take a look at this link. I haven't tried it myself but they say it works. http://tech-tweak.com/2009/05/how-to-make-fake-penusbflash-drive-genuinereset-to-original-capacity.html

Jamiro14

Posted 2011-09-30T06:50:44.703

Reputation: 161