Các bác nếu nên mua bán trên ebay cẩn thận nhé, em vừa được gởi tin nhắn của một member trên ebay đây và em cũng chính là nạn nhân đó. May mắn là có ebay và người bán chịu trả lại tiền cho em, tin nhắn và bài bào kèm theo sau đây các bác xem nhé
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tnimitz0 (153)
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Member since Oct-24-01 in United States
Location: VA, United States
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Dear pterpm,
Greetings,
Please be advised that many high capacity flash drives sold on eBay have faked capacities. Google "ebay test fake usb SOS".
These are low capacity drives that have been hacked so that they report an inflated capacity to Windows. They will operate normally under low usage, but will corrupt data once their "true" capacity is exceeded - potentially leading to massive data loss.
Other buyers have confirmed fake capacity drives sold by rtlsalesllc, so I recommend that you thoroughly test yours. Detecting these fakes is tricky and time consuming. The best test is a tool called h2testw (Google it). You can also test by filling the drive to at least 25% capacity and verifying that the data can be read back *intact*. Data on fakes will typically read back as all zeros after that point.
You cannot trust the capacity shown in windows explorer.
I would be interested in your findings.
If your drive is fake, please leave appropriate feedback to warn other buyers of this scam.
- tnimitz0
Bài báo sau đây trên google với cái firmware tool biến mấy cái usb có mấy chục MB thành 256GB
"Fighting flash fraud on Ebay
The authors of this blog want to elimnate flash fraud on Ebay
h2testw – Gold standard in detecting fake capacity flash
The free program h2testw has proved its worth in detecting flash drives which have been programmed to miss-report capacity (what we now call frankenflash). We give H2testw 1.4 the highest rating and recommend it for testing fraudulently programmed USB Flash Drives for the following reasons:
Easy to Use
Tested to work on 1.1 and 2.0 USB Ports
Tested to work to analyze drives advertised as 4GB, 8GB, 16GB, 32GB and yes …64 GB capacity.
Reports what the operating system sees size to be.
Will write 1 GB files up to the reported size – requiring no work on your part except patience if it is a large drive and a slow computer
Will read all the files it wrote and verify them
Will report that the test ran without problems if all is well
Will produce a detailed report showing the true capacity, how much data has been lost/corrupted and whether there are aliased memory addresses if problems are found.
Output results can easily be copied and pasted into notepad to be saved as a text file.
The program is free
The readme.txt file provides:
Explanation of the program and what it does for general computer users
Information on how to interpret the results
Technical information for those who have a deeper understanding of data storage and file writing and for the skeptics out there.
It has been invaluable to those who (like me) now test all flash they buy (wherever from) to avoid potential data loss arising from use of a falsely programmed device. You can download this free program here:
download h2testw by Harald Bögeholz published by c’t magazine for computer technology
Save the downloaded zip file to your desktop an run the exe file in the folder to install the program on your computer. To test your flash launch the program, select your language (German or English) and select the target drive.
The program will fill your device with numbers and letters in 1000Mb lots and then try to read it back . If your device works as claimed it will tell you that the test ran without problems and you can delete the test files. If not you will get a detailed report.
The results from H2testw have been verified on drives detected as fakes. How?
Drives were dissembled
Controller chips were identified
Flash chips were identified
Searches on the actual flash drives using their identification number revealed their true capacity. These matched the output from the H2testw Program.
In a few cases, when drives were disassembled, epoxy glue removed holding the flash drive to the bottom casing, quality control stickers were found with a size circled. The size? Exactly what H2testw reported as the capacity it could write to. All drives autopsied for investigation and validation of this program were purchased on eBay.
No other program that can match these features has been found. Therefore, H2testw has been adopted as the gold standard in detection of flash that reports a false capacity to the operating system.
However – this program is windows only.
A word to the terrified:
We fully understand the caution people feel about downloading things from the web, the blog authors are also very cautious about this. For anyone who is worried about following the link please be assured that the download page is on the website of a reputable german computer magazine.
The program was written by Harald Bögeholz (who works for the magazine) after they found that the flash drives they gave away a couple of years back were actually fake! The program was originally written for their readers to make up for the mistake. You can follow the link with confidence – or (if you prefer) you can search for the page with google – but for goodness sake if you buy flash memory get the program h2testw!
UPDATE AUGUST 2010: Michel Machado has developed a program for linux users called F3 (after Fight Flash Fraud – how nice!) but reports from those who have used it are a bit inconclusive as to how user-friendly it is if you aren’t very technical. If you want to give it a go you can download F3 here – let us know how you get on if you try this!
UPDATE SEPT 2010: Another Linux programmer has started work on an alternative solution but we don’t know how far he has got yet.
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